Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss
"Grouting" between existing patio slabs: how to avoid dry powdery mortar
29 views
Skip to first unread message
NY
May 30, 2021, 12:48:14 PM5/30/21
to
Our house has a patio of stone slabs (slightly irregular size, shape and
thickness - not rectangular concrete slabs). They seem to have been laid
on bare earth, as far as I can see from looking into the gaps, without
levering up a slab to look.
Some of the mortar "grouting" between the slabs has cracked and
disintegrated, so I'm trying to re-mortar the broken bits. I've removed
the broken bits and brush away as much of the powder residue that
remains. I'm using ready-mixed mortar from B&Q, with water added to form
a stiff paste which is thick enough to adhere to a palette knife so I
can direct it into the gap (typically 5-20 mm) and then tamp it down
with my fingers (wearing rubber gloves in case the cement causes skin
irritation).
I then use the hosepipe to spray a fine mist over the sections every few
hours (given that it's hot and sunny here) so it has enough water to
cause the cement to set.
But some sections never set: even after a couple of days the mortar can
be rubbed away in a powder of sand and cement. Other sections have set
rock solid. The colour of the dry mortar varies from slate grey where
it's set to almost white (maybe with golden sand granules on top) where
it remains powdery after several days.
I've tried various alternative techniques to the stiff-paste consistency:
- adding a bit more water to the mix so it's a bit more runny, and
letting it fall off the palette knife into the gap, building up the
level gradually and then tamping it down to make it roughly level with
the slabs
- filling the section with dry ready-mix and then spraying a mist of
water over to start the setting process: repeating the misting every few
hours
I've checked that all the dry powder is thoroughly wetted, to avoid dry
sections.
No technique seems to give better or worse results. Sometimes sections
set, sometimes they dry to a firm dust that can be rubbed or washed away.
I don't know what the proportions of sand and cement are - just the
standard mortar mix.
I'm making up small batches of a few hundred grammes of dry mix, mixed
in a plastic bowl, so as not to make so much that it has started to set
before I've finished the painstaking job of tamping the mortar into the
gaps.
Should I try soaking the ground through the cracks that I'm about to
fill, to prevent the water in the mortar leaching into the ground before
it has had chance to set the mortar?
I don't need it to be a perfect job, as long as there are no longer gaps
that weeds can grow through.
thickness - not rectangular concrete slabs). They seem to have been laid
on bare earth, as far as I can see from looking into the gaps, without
levering up a slab to look.
Some of the mortar "grouting" between the slabs has cracked and
disintegrated, so I'm trying to re-mortar the broken bits. I've removed
the broken bits and brush away as much of the powder residue that
remains. I'm using ready-mixed mortar from B&Q, with water added to form
a stiff paste which is thick enough to adhere to a palette knife so I
can direct it into the gap (typically 5-20 mm) and then tamp it down
with my fingers (wearing rubber gloves in case the cement causes skin
irritation).
I then use the hosepipe to spray a fine mist over the sections every few
hours (given that it's hot and sunny here) so it has enough water to
cause the cement to set.
But some sections never set: even after a couple of days the mortar can
be rubbed away in a powder of sand and cement. Other sections have set
rock solid. The colour of the dry mortar varies from slate grey where
it's set to almost white (maybe with golden sand granules on top) where
it remains powdery after several days.
I've tried various alternative techniques to the stiff-paste consistency:
- adding a bit more water to the mix so it's a bit more runny, and
letting it fall off the palette knife into the gap, building up the
level gradually and then tamping it down to make it roughly level with
the slabs
- filling the section with dry ready-mix and then spraying a mist of
water over to start the setting process: repeating the misting every few
hours
I've checked that all the dry powder is thoroughly wetted, to avoid dry
sections.
No technique seems to give better or worse results. Sometimes sections
set, sometimes they dry to a firm dust that can be rubbed or washed away.
I don't know what the proportions of sand and cement are - just the
standard mortar mix.
I'm making up small batches of a few hundred grammes of dry mix, mixed
in a plastic bowl, so as not to make so much that it has started to set
before I've finished the painstaking job of tamping the mortar into the
gaps.
Should I try soaking the ground through the cracks that I'm about to
fill, to prevent the water in the mortar leaching into the ground before
it has had chance to set the mortar?
I don't need it to be a perfect job, as long as there are no longer gaps
that weeds can grow through.
NY
May 30, 2021, 1:13:39 PM5/30/21
to
On 30/05/2021 17:48, NY wrote:
> Our house has a patio of stone slabs (slightly irregular size, shape and
> thickness - not rectangular concrete slabs). They seem to have been laid
> on bare earth, as far as I can see from looking into the gaps, without
> levering up a slab to look.
>
> Some of the mortar "grouting" between the slabs has cracked and
> disintegrated, so I'm trying to re-mortar the broken bits. I've removed
> the broken bits and brush away as much of the powder residue that
> remains. I'm using ready-mixed mortar from B&Q, with water added to form
> a stiff paste which is thick enough to adhere to a palette knife so I
> can direct it into the gap (typically 5-20 mm) and then tamp it down
> with my fingers (wearing rubber gloves in case the cement causes skin
> irritation).
I forgot to say: the mortar is brand new and the bag was only opened a
> Our house has a patio of stone slabs (slightly irregular size, shape and
> thickness - not rectangular concrete slabs). They seem to have been laid
> on bare earth, as far as I can see from looking into the gaps, without
> levering up a slab to look.
>
> Some of the mortar "grouting" between the slabs has cracked and
> disintegrated, so I'm trying to re-mortar the broken bits. I've removed
> the broken bits and brush away as much of the powder residue that
> remains. I'm using ready-mixed mortar from B&Q, with water added to form
> a stiff paste which is thick enough to adhere to a palette knife so I
> can direct it into the gap (typically 5-20 mm) and then tamp it down
> with my fingers (wearing rubber gloves in case the cement causes skin
> irritation).
few days ago and has been kept in a dry garage.
It's made with grey Portland cement, not white lime.
NY
May 30, 2021, 1:40:16 PM5/30/21
to
"NY" <m...@privacy.net> wrote in message
news:Z8udnbFPsIldWi79...@brightview.co.uk...
Another thing I forgot to say. Where I've dug up the loose mortar from when
the patio was first laid (about 10 years, according to neighbours), it's
been a thin crust, in some places only about 5 mm thick, with a large void
below it down to the level of the base on which the slabs have been laid. Is
this normal? I'd have thought the whole depth of the crack between slabs
would have been filled with mortar.
news:Z8udnbFPsIldWi79...@brightview.co.uk...
the patio was first laid (about 10 years, according to neighbours), it's
been a thin crust, in some places only about 5 mm thick, with a large void
below it down to the level of the base on which the slabs have been laid. Is
this normal? I'd have thought the whole depth of the crack between slabs
would have been filled with mortar.
RobH
May 30, 2021, 1:47:46 PM5/30/21
to
on a bed of sharp sand / cement mixed at about 7 or 8:1. I have had to
re point the gaps about 3/4 times since and I use a 3:1 mix of builders
sand and cement with just enough water to make it damp and no more. .
That works of for me.
Laying the slabs on bare soil is not a good idea for a start.
Rod Speed
May 30, 2021, 1:57:18 PM5/30/21
to
"RobH" <r...@despammer.com> wrote in message
news:ihi1dt...@mid.individual.net...
NY
May 30, 2021, 2:41:41 PM5/30/21
to
> When I laid my patio , about 20 years ago, I put all the pavers / slabs on
> a bed of sharp sand / cement mixed at about 7 or 8:1. I have had to re
> point the gaps about 3/4 times since and I use a 3:1 mix of builders sand
> and cement with just enough water to make it damp and no more. .
>
> That works of for me.
"Just enough water to make it damp and no more" sounds similar to the
> a bed of sharp sand / cement mixed at about 7 or 8:1. I have had to re
> point the gaps about 3/4 times since and I use a 3:1 mix of builders sand
> and cement with just enough water to make it damp and no more. .
>
> That works of for me.
consistency I've used. I found that any more runny was very difficult to
direct into the gap without it dribbling over the surface of the slabs and
having to be wiped off afterwards; it also led to patches of golden sand in
the wet mixture, rather than the grains of sand remaining coated in grey
cement.
There seems to be no rhyme or reason to which parts set like stone and which
remain the consistency of damp sand. The very first batch I made was partly
used to fill a couple of holes in the rendering on the brick wall of the
house (and that has set solid), but the rest of the same batch has set hard
in places but there are patches which haven't set -- and that's for the same
batch, all used within about 30 minutes.
I'm getting a success rate of about 1/3 ie 2/3 of what I've done will have
to be gouged out with a screwdriver and washed out so I can redo it .
How long does mortar remain workable after it has been made? I presume if it
was starting to set before I'd finished using it, it would get noticeably
more stiff and lumpy, rather than remaining a smooth paste. I'm sure I'm
getting each batch used within about 30 minutes of adding water to the dry
mix.
Is the porosity of the base that the slabs are laid on relevant? Am I right
in wondering if the "just enough water to make it damp and no more" mortar
is drying out by water leaching into the ground (or evaporating from the
surface on a hot day) before the water has had chance to react with the
cement to make it set around the sand?
The ready-mix is made by Tarmac (ie it's not B&Q's own brand of dubious
quality) and the label says "cement 15% aggregates 85%". That's a ratio of
about 5.5:1 - quite a bit less cement than the figure of between 3:1 and 4:1
that I've seen mentioned everywhere. Surprisingly the mixture ratio is not
advertised in large letters - I had to search the various paragraphs of
small print to find the 15%/85% figure.
A lot of what I see when I google "grouting/filling gaps in patio slabs"
makes it sound very easy, so there's obviously something I'm not doing
right!
Peeler
May 30, 2021, 3:21:12 PM5/30/21
to
On Mon, 31 May 2021 03:57:11 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:
> Not
LOL Senile pest!
--
Kerr-Mudd,John addressing the auto-contradicting senile cretin:
"Auto-contradictor Rod is back! (in the KF)"
MID: <XnsA97071CF43...@85.214.115.223>
Speed, the auto-contradicting senile sociopath, blabbered, again:
> Not
LOL Senile pest!
--
Kerr-Mudd,John addressing the auto-contradicting senile cretin:
"Auto-contradictor Rod is back! (in the KF)"
MID: <XnsA97071CF43...@85.214.115.223>
noth...@aolbin.com
May 30, 2021, 4:56:53 PM5/30/21
to
On 30/05/2021 17:48, NY wrote:
brush-in the dry mix, brush any cement powder off the surface of the
slab and then to sprinkle a *small* amount of water on the joints and
let nature (humidity and/or light rain) take its course. By doing that
you fill the gaps, get a strong mortar and don't smudge the slabs.
williamwright
May 30, 2021, 5:24:37 PM5/30/21
to
On 30/05/2021 17:48, NY wrote:
> Some of the mortar "grouting" between the slabs has cracked and
> disintegrated, > Some of the mortar "grouting" between the slabs has cracked and
> disintegrated,
Wait until it's been dry weather for a few days, then tip a good mortar
mix, dry, onto the slabs, and brush it around until it goes into the
cracks. Then go round bashing the slabs with a big lump of wood to
vibrate them, then brush some more in. Then leave it alone for a couple
of weeks, unless you're in a very dry area, in which case sprinkle a bit
of water gently all over and cover it with polythene.
Bill
Rod Speed
May 30, 2021, 6:51:54 PM5/30/21
to
"NY" <m...@privacy.invalid> wrote in message
news:s90m92$t8q$1...@dont-email.me...
> "RobH" <r...@despammer.com> wrote in message
> news:ihi1dt...@mid.individual.net...
>> When I laid my patio , about 20 years ago, I put all the pavers / slabs
>> on a bed of sharp sand / cement mixed at about 7 or 8:1. I have had to
>> re point the gaps about 3/4 times since and I use a 3:1 mix of builders
>> sand and cement with just enough water to make it damp and no more. .
>>
>> That works of for me.
>
> "Just enough water to make it damp and no more" sounds similar to the
> consistency I've used. I found that any more runny was very difficult to
> direct into the gap without it dribbling over the surface of the slabs and
> having to be wiped off afterwards; it also led to patches of golden sand
> in the wet mixture, rather than the grains of sand remaining coated in
> grey cement.
> There seems to be no rhyme or reason to which parts set like stone and
> which remain the consistency of damp sand.
But there must be.
> news:ihi1dt...@mid.individual.net...
>> When I laid my patio , about 20 years ago, I put all the pavers / slabs
>> on a bed of sharp sand / cement mixed at about 7 or 8:1. I have had to
>> re point the gaps about 3/4 times since and I use a 3:1 mix of builders
>> sand and cement with just enough water to make it damp and no more. .
>>
>> That works of for me.
>
> "Just enough water to make it damp and no more" sounds similar to the
> consistency I've used. I found that any more runny was very difficult to
> direct into the gap without it dribbling over the surface of the slabs and
> having to be wiped off afterwards; it also led to patches of golden sand
> in the wet mixture, rather than the grains of sand remaining coated in
> grey cement.
> There seems to be no rhyme or reason to which parts set like stone and
> which remain the consistency of damp sand.
> The very first batch I made was partly used to fill a couple of holes in
> the rendering on the brick wall of the house (and that has set solid),
> but the rest of the same batch has set hard in places but there are
> patches which haven't set -- and that's for the same batch, all used
> within about 30 minutes.
the mixture is in the gap between the slabs, you
are washing the cement out. You arent adding
water later with the holes in the render on the
brick wall of the house.
> I'm getting a success rate of about 1/3 ie 2/3 of what I've done will have
> to be gouged out with a screwdriver and washed out so I can redo it .
> How long does mortar remain workable after it has been made?
> I presume if it was starting to set before I'd finished using it, it would
> get noticeably more stiff and lumpy, rather than remaining a smooth paste.
> I'm sure I'm getting each batch used within about 30 minutes of adding
> water to the dry mix.
> Is the porosity of the base that the slabs are laid on relevant?
> Am I right in wondering if the "just enough water to make it damp and no
> more" mortar is drying out by water leaching into the ground (or
> evaporating from the surface on a hot day) before the water has had chance
> to react with the cement to make it set around the sand?
The Natural Philosopher
May 31, 2021, 3:52:25 AM5/31/21
to
On 30/05/2021 19:41, NY wrote:
> A lot of what I see when I google "grouting/filling gaps in patio slabs"
> makes it sound very easy, so there's obviously something I'm not doing
> right!
if you are getting non setting crumbly shit there is not enough cement
> A lot of what I see when I google "grouting/filling gaps in patio slabs"
> makes it sound very easy, so there's obviously something I'm not doing
> right!
the problem with a pre iced bag is that it may after a while not have
the mixture uniform and if you use it in small quantities you may get
all cement or no cement.
It better to buy separately for small jobs and it doesn't cost a lot more
--
“People believe certain stories because everyone important tells them,
and people tell those stories because everyone important believes them.
Indeed, when a conventional wisdom is at its fullest strength, one’s
agreement with that conventional wisdom becomes almost a litmus test of
one’s suitability to be taken seriously.”
Paul Krugman
Chris Green
May 31, 2021, 4:18:07 AM5/31/21
to
The Natural Philosopher <t...@invalid.invalid> wrote:
> On 30/05/2021 19:41, NY wrote:
> > A lot of what I see when I google "grouting/filling gaps in patio slabs"
> > makes it sound very easy, so there's obviously something I'm not doing
> > right!
> if you are getting non setting crumbly shit there is not enough cement
>
> the problem with a pre iced bag is that it may after a while not have
> the mixture uniform and if you use it in small quantities you may get
> all cement or no cement.
>
> It better to buy separately for small jobs and it doesn't cost a lot more
>
I've been doing some of this recently, I have separate cement and sand
> On 30/05/2021 19:41, NY wrote:
> > A lot of what I see when I google "grouting/filling gaps in patio slabs"
> > makes it sound very easy, so there's obviously something I'm not doing
> > right!
> if you are getting non setting crumbly shit there is not enough cement
>
> the problem with a pre iced bag is that it may after a while not have
> the mixture uniform and if you use it in small quantities you may get
> all cement or no cement.
>
> It better to buy separately for small jobs and it doesn't cost a lot more
>
and I've been using a 'strong' mix of maybe 2 or 3 sand to 1 cement.
I've also been using a pretty wet sort of mix which makes it easy to
get it into the gaps, they are cement slabs so a bit of splash round
the edges doesn't matter at all. The results seem pretty solid so far
(but it has only been done for a month or so).
--
Chris Green
·
Peeler
May 31, 2021, 4:23:33 AM5/31/21
to
On Mon, 31 May 2021 08:51:46 +1000, cantankerous trolling geezer Rodent
--
"Who or What is Rod Speed?
Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed
is an insecure and worthless individual who has discovered he can
enhance his own self-esteem in his own eyes by playing "the big, hard
man" on the InterNet."
https://www.pcreview.co.uk/threads/rod-speed-faq.2973853/
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the trolling senile asshole's latest trollshit unread>
--
"Who or What is Rod Speed?
Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed
is an insecure and worthless individual who has discovered he can
enhance his own self-esteem in his own eyes by playing "the big, hard
man" on the InterNet."
https://www.pcreview.co.uk/threads/rod-speed-faq.2973853/
RobH
May 31, 2021, 5:18:51 AM5/31/21
to
I'm not a builder so I have been learning as I go along so to speak.
Also I put it down to frost / extremely cold weather that has caused the
mortar to break up or go crumbly on the surface
charles
May 31, 2021, 5:55:11 AM5/31/21
to
In article <ihjnvm...@mid.individual.net>,
When we moved into this house 44 years ago, the previous owner had left a
pile to irregularly shaped paving for a path at the side of the house.
He's already laid a terrace at the back of the house. I laid the path and
40+ years later it's still looking good - no cracks between the slabs. On
the other hand, the terrace .....
--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle
pile to irregularly shaped paving for a path at the side of the house.
He's already laid a terrace at the back of the house. I laid the path and
40+ years later it's still looking good - no cracks between the slabs. On
the other hand, the terrace .....
--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle
Rod Speed
May 31, 2021, 6:02:05 AM5/31/21
to
news:ihjnvm...@mid.individual.net...
Still nothing like what it should be. You don’t have to repoint
brickwork at anything even remotely like a 7 year interval.
> I'm not a builder so I have been learning as I go along so to speak. Also
> I put it down to frost / extremely cold weather that has caused the mortar
> to break up or go crumbly on the surface
You don’t get that with brickwork either.
brickwork at anything even remotely like a 7 year interval.
> I'm not a builder so I have been learning as I go along so to speak. Also
> I put it down to frost / extremely cold weather that has caused the mortar
> to break up or go crumbly on the surface
Andrew
May 31, 2021, 7:49:23 AM5/31/21
to
That sounds more like postcrete or concrete mix.
You need a bag of sand and a smaller bag of portland cement and
make up a 5:1 mix of sand:cement.
Peeler
May 31, 2021, 8:03:10 AM5/31/21
to
On Mon, 31 May 2021 20:01:55 +1000, cantankerous trolling geezer Rodent
"You can fuck off as you know less than pig shit you sad
little ignorant cunt."
MID: <62dcaae57b421e2b...@haph.org>
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the trolling senile asshole's latest trollshit unread>
--
"Anonymous" to trolling senile Rodent Speed:
<FLUSH the trolling senile asshole's latest trollshit unread>
--
"You can fuck off as you know less than pig shit you sad
little ignorant cunt."
MID: <62dcaae57b421e2b...@haph.org>
RobH
May 31, 2021, 8:06:23 AM5/31/21
to
builder what should I have done, ie method, mix or anything else, so it
doesn't crack, crumble or break up with cold weather.
NY
May 31, 2021, 9:40:42 AM5/31/21
to
"Andrew" <Andrew9...@mybtinternet.com> wrote in message
news:s92ifs$17lb$1...@gioia.aioe.org...
That's not *too* far from the 5:1 that you suggest. If I need to buy any
more (depends how long the 25 kg bag of pre-mixed lasts) then I might buy
separate sand and cement and make up a slightly stronger (more cement) mix.
Is 5:1 enough? I've seen some web sites which recommend 4:1 or even 3:1.
The bag is definitely labelled "mortar". B&Q did also sell other bags
labelled "post mix".
I've done some more mortaring today, so I'll see how it sets. A patch of the
mortar that I did three days ago had dried to an almost white solid which
was actually cement/sand dust (almost like the un-wetted stuff I bought!)
even though I'd mixed it to a stiff paste just like all the other batches. I
prodded it with a screwdriver and I was left with dust - I was *almost*
tempted to mix it back to a paste with water and reuse it ;-)
I presume I want builder's sand, if I buy it separately.
Is there any significance in the colour of the "set" mortar? Dark grey
(after three days) is rock solid. Much lighter grey seems to be powder. And
that's light grey all the way through, so it's not just the surface that has
more cement to sand that what's underneath.
I'll see how it goes. It's a long slow job because the more I look the more
I find grouting that has cracked and can be pushed down into the void
between the slabs, or has turned to dust. Not sure how long ago it was
done - maybe 10 years. The cracking all occurred this more recent winter
(frost?), after looking fine before that.
When I've finished that, I need to make up wooden ramps so we can wheel a
trolley (*) up and down between three different levels of patio - and the
step height is different in each case.
(*) For bringing up loads of wood/peat/sawdust-blocks for the wood-burning
stove, and for moving loads of plant pots of bulbs onto the patio in time
for daffodils etc to flower, and then off the patio to make way for other
things in the summer.
news:s92ifs$17lb$1...@gioia.aioe.org...
> If the bag says 85% aggregates then you have bought the wrong stuff.
> That sounds more like postcrete or concrete mix.
>
> You need a bag of sand and a smaller bag of portland cement and
> make up a 5:1 mix of sand:cement.
85% sand : 15% cement is 5.7:1 (ie 85/15 : 1)
> That sounds more like postcrete or concrete mix.
>
> You need a bag of sand and a smaller bag of portland cement and
> make up a 5:1 mix of sand:cement.
That's not *too* far from the 5:1 that you suggest. If I need to buy any
more (depends how long the 25 kg bag of pre-mixed lasts) then I might buy
separate sand and cement and make up a slightly stronger (more cement) mix.
Is 5:1 enough? I've seen some web sites which recommend 4:1 or even 3:1.
The bag is definitely labelled "mortar". B&Q did also sell other bags
labelled "post mix".
I've done some more mortaring today, so I'll see how it sets. A patch of the
mortar that I did three days ago had dried to an almost white solid which
was actually cement/sand dust (almost like the un-wetted stuff I bought!)
even though I'd mixed it to a stiff paste just like all the other batches. I
prodded it with a screwdriver and I was left with dust - I was *almost*
tempted to mix it back to a paste with water and reuse it ;-)
I presume I want builder's sand, if I buy it separately.
Is there any significance in the colour of the "set" mortar? Dark grey
(after three days) is rock solid. Much lighter grey seems to be powder. And
that's light grey all the way through, so it's not just the surface that has
more cement to sand that what's underneath.
I'll see how it goes. It's a long slow job because the more I look the more
I find grouting that has cracked and can be pushed down into the void
between the slabs, or has turned to dust. Not sure how long ago it was
done - maybe 10 years. The cracking all occurred this more recent winter
(frost?), after looking fine before that.
When I've finished that, I need to make up wooden ramps so we can wheel a
trolley (*) up and down between three different levels of patio - and the
step height is different in each case.
(*) For bringing up loads of wood/peat/sawdust-blocks for the wood-burning
stove, and for moving loads of plant pots of bulbs onto the patio in time
for daffodils etc to flower, and then off the patio to make way for other
things in the summer.
Roger Hayter
May 31, 2021, 10:25:43 AM5/31/21
to
bears no simple (AFAIK) relation to proportions by weight. And secondly, a
bag of mortar mix separates in store (if indeed the contents were ever mixed)
and the whole bagful needs thorough mixing in a tub or barrow before taking
some out to mix with water.
--
Roger Hayter
Brian Gaff (Sofa)
May 31, 2021, 11:23:08 AM5/31/21
to
No he needs to bite the bullet and look under one and see what was done
properly. If its on soil, depending on the composition, round here its got
a lot of clay, the soil swells and contracts, as I found at a feeble attempt
at crazy paving some years ago!
That is enough to crack any cement between stones.
As for drying but not setting, is it the narrowest slits that dry out? I
would imagine that would be the case. Cement is not very strong unless under
compression and the less there is the less the compression and the more it
turns to just powder again.
Brian
--
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
properly. If its on soil, depending on the composition, round here its got
a lot of clay, the soil swells and contracts, as I found at a feeble attempt
at crazy paving some years ago!
That is enough to crack any cement between stones.
As for drying but not setting, is it the narrowest slits that dry out? I
would imagine that would be the case. Cement is not very strong unless under
compression and the less there is the less the compression and the more it
turns to just powder again.
Brian
--
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
bri...@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
R D S
May 31, 2021, 11:29:37 AM5/31/21
to
On 30/05/2021 17:48, NY wrote:
> Our house has a patio of stone slabs (slightly irregular size, shape and
> thickness - not rectangular concrete slabs). They seem to have been laid
> on bare earth, as far as I can see from looking into the gaps, without
> levering up a slab to look.
>
> Some of the mortar "grouting" between the slabs has cracked and
> disintegrated, so I'm trying to re-mortar the broken bits.
Have you ruled out joint compound?
> thickness - not rectangular concrete slabs). They seem to have been laid
> on bare earth, as far as I can see from looking into the gaps, without
> levering up a slab to look.
>
> Some of the mortar "grouting" between the slabs has cracked and
> disintegrated, so I'm trying to re-mortar the broken bits.
I've just laid a new patio and i'm deciding what to do as the jointing
compound is expensive, but if it outlives mortar it might be worth it.
Rod Speed
May 31, 2021, 4:27:14 PM5/31/21
to
news:ihk1pr...@mid.individual.net...
Do a better job of point the slabs, correct mix, correct
water level, correct time of year when doing it.
water level, correct time of year when doing it.
Peeler
May 31, 2021, 5:11:40 PM5/31/21
to
On Tue, 1 Jun 2021 06:27:07 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the trolling senile asshole's latest trollshit unread>
--
<FLUSH the trolling senile asshole's latest trollshit unread>
--
RobH
May 31, 2021, 6:01:44 PM5/31/21
to
What is the correct mix if not 3:1
What is the correct water level if not just enough to dampen the mix
And finally what is the correct time of year to do the job.
Thanks
Rod Speed
May 31, 2021, 6:23:41 PM5/31/21
to
news:ihl4m4...@mid.individual.net...
That’s your problem. That’s not what is done with bricklaying.
> And finally what is the correct time of year to do the job.
When the cement isnt washed away.
> And finally what is the correct time of year to do the job.
Peeler
May 31, 2021, 6:26:20 PM5/31/21
to
On Tue, 1 Jun 2021 08:23:32 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the trolling senile pest's latest trollshit unread>
RobH
Jun 1, 2021, 2:50:09 AM6/1/21
to
Bricklaying is a different matter as it is vertical, slab laying is
horizontal and therefore more chance of frost and ice adhering to the
mortar.
The cement is not washed away, as I did not say it was.
Never mind, if you don't know, some one else will tell me.
The Natural Philosopher
Jun 1, 2021, 6:44:55 AM6/1/21
to
On 01/06/2021 07:50, RobH wrote:
> The cement is not washed away, as I did not say it was.
> Never mind, if you don't know, some one else will tell me.
best time is when its about half as hot as it gets, and is damp. so cool
> The cement is not washed away, as I did not say it was.
> Never mind, if you don't know, some one else will tell me.
and damp. cement will set, slowly, wont get washed away by rain, and
slabs wont expand as hot. don't want overnight frosts that will destroy
it before its sets either
--
"When one man dies it's a tragedy. When thousands die it's statistics."
Josef Stalin
RobH
Jun 1, 2021, 8:48:59 AM6/1/21
to
On 01/06/2021 11:44, The Natural Philosopher wrote:
> On 01/06/2021 07:50, RobH wrote:
>> The cement is not washed away, as I did not say it was.
>> Never mind, if you don't know, some one else will tell me.
>
> best time is when its about half as hot as it gets, and is damp. so cool
> and damp. cement will set, slowly, wont get washed away by rain, and
> slabs wont expand as hot. don't want overnight frosts that will destroy
> it before its sets either
>
>
Thanks, as I normally or have done it either spring time or maybe
> On 01/06/2021 07:50, RobH wrote:
>> The cement is not washed away, as I did not say it was.
>> Never mind, if you don't know, some one else will tell me.
>
> best time is when its about half as hot as it gets, and is damp. so cool
> and damp. cement will set, slowly, wont get washed away by rain, and
> slabs wont expand as hot. don't want overnight frosts that will destroy
> it before its sets either
>
>
September when needed.
When I have looked up what mix and how much water, all I found was
anything between 4:1 and 3:1, and just enough water so it clags or holds
in your hand. Then trowel it in the gaps, and tamping it down as I go
along. I also us a 'iron' to smooth each joint, then lightly water
afterwards, then leave it dry off
The Natural Philosopher
Jun 1, 2021, 9:38:00 AM6/1/21
to
crumbly and leaves spaces fir water which freezes. 2:1 is hitler bunker
grade.
It doesn't matter how much water you add - not as far as setting goes,
as anyone who has left a bag of opened cement over winter will tell you,
It absorbs all the CO2 and H2O it needs from the air...
My technique is utterly amateur. I mash it in with fingerss, a trowel -
anything and its sort of mud pie consistency
Then I remove the excess with a damp sponge RINSING EVERY STROKE
That is the key., what's left is a faint cement film and brick acid
washes that off.
--
A lie can travel halfway around the world while the truth is putting on
its shoes.
Andrew
Jun 1, 2021, 10:34:36 AM6/1/21
to
It is possible that the bag had been in store for awhile and had a
small hole or other damage which has allowed the cement fines to
start to set but without turning the whole lot hard. It's possible
instore staff had noticed some harness and bashed it to break up any
fine lumps. This is never going to be any use for a decent mortar.
Also, when mixed and a proper admix used it should give a nice
'fatty' mortar. If it doesn't, don't use it. If the soil is liable
to 'heave' in cold weather, a lime-based mortar might be better but
this needs weather protection while it achieves full strngth.
Also possible that the whole batch was poorly mixed by the store
supplier and has less cement than it should.
For grouting slabs, it must be protected from frost for at least
7 days.
small hole or other damage which has allowed the cement fines to
start to set but without turning the whole lot hard. It's possible
instore staff had noticed some harness and bashed it to break up any
fine lumps. This is never going to be any use for a decent mortar.
Also, when mixed and a proper admix used it should give a nice
'fatty' mortar. If it doesn't, don't use it. If the soil is liable
to 'heave' in cold weather, a lime-based mortar might be better but
this needs weather protection while it achieves full strngth.
Also possible that the whole batch was poorly mixed by the store
supplier and has less cement than it should.
For grouting slabs, it must be protected from frost for at least
7 days.
Tricky Dicky
Jun 1, 2021, 11:30:34 AM6/1/21
to
On Sunday, May 30, 2021 at 5:48:14 PM UTC+1, NY wrote:
> Our house has a patio of stone slabs (slightly irregular size, shape and
> thickness - not rectangular concrete slabs). They seem to have been laid
> on bare earth, as far as I can see from looking into the gaps, without
> levering up a slab to look.
>
> Some of the mortar "grouting" between the slabs has cracked and
> disintegrated, so I'm trying to re-mortar the broken bits. I've removed
> the broken bits and brush away as much of the powder residue that
> remains. I'm using ready-mixed mortar from B&Q, with water added to form
> a stiff paste which is thick enough to adhere to a palette knife so I
> can direct it into the gap (typically 5-20 mm) and then tamp it down
> with my fingers (wearing rubber gloves in case the cement causes skin
> irritation).
>
> I then use the hosepipe to spray a fine mist over the sections every few
> Our house has a patio of stone slabs (slightly irregular size, shape and
> thickness - not rectangular concrete slabs). They seem to have been laid
> on bare earth, as far as I can see from looking into the gaps, without
> levering up a slab to look.
>
> Some of the mortar "grouting" between the slabs has cracked and
> disintegrated, so I'm trying to re-mortar the broken bits. I've removed
> the broken bits and brush away as much of the powder residue that
> remains. I'm using ready-mixed mortar from B&Q, with water added to form
> a stiff paste which is thick enough to adhere to a palette knife so I
> can direct it into the gap (typically 5-20 mm) and then tamp it down
> with my fingers (wearing rubber gloves in case the cement causes skin
> irritation).
>
> hours (given that it's hot and sunny here) so it has enough water to
> cause the cement to set.
>
> But some sections never set: even after a couple of days the mortar can
> be rubbed away in a powder of sand and cement. Other sections have set
> rock solid. The colour of the dry mortar varies from slate grey where
> it's set to almost white (maybe with golden sand granules on top) where
> it remains powdery after several days.
>
> I've tried various alternative techniques to the stiff-paste consistency:
>
> - adding a bit more water to the mix so it's a bit more runny, and
> letting it fall off the palette knife into the gap, building up the
> level gradually and then tamping it down to make it roughly level with
> the slabs
>
> - filling the section with dry ready-mix and then spraying a mist of
> water over to start the setting process: repeating the misting every few
> hours
>
> I've checked that all the dry powder is thoroughly wetted, to avoid dry
> sections.
>
> No technique seems to give better or worse results. Sometimes sections
> set, sometimes they dry to a firm dust that can be rubbed or washed away.
>
> I don't know what the proportions of sand and cement are - just the
> standard mortar mix.
>
> I'm making up small batches of a few hundred grammes of dry mix, mixed
> in a plastic bowl, so as not to make so much that it has started to set
> before I've finished the painstaking job of tamping the mortar into the
> gaps.
>
>
> Should I try soaking the ground through the cracks that I'm about to
> fill, to prevent the water in the mortar leaching into the ground before
> it has had chance to set the mortar?
>
>
> I don't need it to be a perfect job, as long as there are no longer gaps
> that weeds can grow through.
I have used this stuff just to seal up a mowing strip, it is easy peasie to use and gives a good hard wearing finish and importantly no staining.
https://www.bcprofiles.co.uk/product/azpects-easy-joint-paving-jointing-compound-12-5kg-stone-grey/
Richard
Rod Speed
Jun 1, 2021, 2:54:57 PM6/1/21
to
news:ihm3kt...@mid.individual.net...
The mix is fine, I would have said if it wasn’t.
> and water level.
I did in fact answer that one.
> Bricklaying is a different matter as it is vertical, slab laying is
> horizontal and therefore more chance of frost and ice adhering to the
> mortar.
That’s wrong with garden walls etc.
> The cement is not washed away, as I did not say it was.
It must be if you don’t get permanent grout.
> Never mind, if you don't know, some one else will tell me.
I do know and did tell you.
> and water level.
I did in fact answer that one.
> Bricklaying is a different matter as it is vertical, slab laying is
> horizontal and therefore more chance of frost and ice adhering to the
> mortar.
> The cement is not washed away, as I did not say it was.
> Never mind, if you don't know, some one else will tell me.
Peeler
Jun 1, 2021, 3:24:42 PM6/1/21
to
On Wed, 2 Jun 2021 04:54:50 +1000, cantankerous trolling geezer Rodent
--
dennis@home to retarded trolling senile Rodent:
"sod off rod you don't have a clue about anything."
Message-ID: <uV9lE.196195$cx5....@fx46.iad>
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the trolling senile asshole's latest trollshit unread>
--
dennis@home to retarded trolling senile Rodent:
"sod off rod you don't have a clue about anything."
Message-ID: <uV9lE.196195$cx5....@fx46.iad>
Rod Speed
Jun 1, 2021, 3:24:54 PM6/1/21
to
RobH <r...@despammer.com> wrote
> The Natural Philosopher wrote
You clearly arent doing it right if you have to keep redoing it so often.
Like I said, the mix is fine, so it must be the water or the time when you
do it.
Its not rocket science, others manage to get it right.
> The Natural Philosopher wrote
Like I said, the mix is fine, so it must be the water or the time when you
do it.
Its not rocket science, others manage to get it right.
charles
Jun 1, 2021, 3:51:37 PM6/1/21
to
In article <ihnfs1...@mid.individual.net>, Rod Speed
Could it be that the product is not properly mixed in the bag?
Peeler
Jun 1, 2021, 3:58:16 PM6/1/21
to
On Wed, 2 Jun 2021 05:24:46 +1000, cantankerous trolling geezer Rodent
cretin's pathological trolling:
https://www.pcreview.co.uk/threads/rod-speed-faq.2973853/
Speed, the auto-contradicting senile sociopath, blabbered, again:
<FLUSH the trolling senile asshole's latest trollshit unread>
--
Website (from 2007) dedicated to the 86-year-old senile Australian
<FLUSH the trolling senile asshole's latest trollshit unread>
--
cretin's pathological trolling:
https://www.pcreview.co.uk/threads/rod-speed-faq.2973853/
The Natural Philosopher
Jun 1, 2021, 4:00:49 PM6/1/21
to
On 01/06/2021 20:40, charles wrote:
> Could it be that the product is not properly mixed in the bag?
Of course that's the problem. But it takes 30 armchair experts to
> Could it be that the product is not properly mixed in the bag?
completely confuse the OP
--
In a Time of Universal Deceit, Telling the Truth Is a Revolutionary Act.
- George Orwell
Rod Speed
Jun 1, 2021, 4:54:21 PM6/1/21
to
"charles" <cha...@candehope.me.uk> wrote in message
news:5935e88b...@candehope.me.uk...
ratio.
0 new messages