Laying chipboard floor over screed
pcb1962
Question is, should I bond the board to the concrete, and if so what
with?
If I don't bond it I'm a bit worried about having bouncy bits in the
middle if the screed isn't perfectly flat, or if the wood expands
after laying. On the other hand, if I glue it and the wood tries to
expand am I in trouble? I was thinking about just spreading a load of
pva on the floor and laying the sheets on that, is that a good or bad
idea? Perhaps a more flexible bond would be better allowing the boards
a little bit of movement.
(The screed was layed last year with dpc and insulation, no likelihood
of damp problems).
Thanks for any advice.
kdb...@gmail.com
the chipboard on top of these rather than directly on top of the
concrete. This will raise the level of the floor by another 19 - 25mm
depending on the battens you use though. Can't say I'd be comfortable
with it just glued.
Franko
"pcb1962" <pe...@pandasys.co.uk> wrote in message
news:8f39c01f-3197-4e4d...@r13g2000vbr.googlegroups.com...
The last thing I'd think of doing myself is bonding the flooring directly to
the screed, especially if you think you may need to lift it at some point in
the future.
Could you not just lay the thin foam as used under laminate flooring, it
would take care of minimal discrepancies in the screed.
I would think that as long as you leave expansion gaps around the perimeter,
you wouldn't have a problem with expansion.
Franko.
slider
"pcb1962" <pe...@pandasys.co.uk> wrote in message
news:8f39c01f-3197-4e4d...@r13g2000vbr.googlegroups.com...
Why are you wanting to lay boards down?
PeterCB
A number of reasons, primarily for load spreading. Between the screed
and the slab below is Celotex insulation block. From what I could see
when they were laying it, the screed is only a couple of inches thick
over the celotex, and I don't feel comfortable with the load bearing
ability of that construction were I to put my half-ton lathe and 300kg
mill directly onto the floor as it is. So my plan is to lay 22mm
moisture resistant t+g chipboard over the screed to spread the load.
Also although I could paint the screed with garage floor paint it
seems a bit dry and crumbly to use long term without any covering.
Dave Plowman (News)
<8f39c01f-3197-4e4d...@r13g2000vbr.googlegroups.com>,
Most new houses that use this idea have polystyrene sheet - perhaps 2"
thick or so - between concrete and chipboard. But I'd guess that would
raise the floor height too much. Not sure why you want to do this though -
chipboard won't add any 'bounce' to the floor.
--
*I'm not being rude. You're just insignificant
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.
The Natural Philosopher
> In article
> <8f39c01f-3197-4e4d...@r13g2000vbr.googlegroups.com>,
> pcb1962 <pe...@pandasys.co.uk> wrote:
>> Planning to cover a screeded floor with 8x2 t+g chipboard sheets.
>> Question is, should I bond the board to the concrete, and if so what
>> with?
>> If I don't bond it I'm a bit worried about having bouncy bits in the
>> middle if the screed isn't perfectly flat, or if the wood expands
>> after laying. On the other hand, if I glue it and the wood tries to
>> expand am I in trouble? I was thinking about just spreading a load of
>> pva on the floor and laying the sheets on that, is that a good or bad
>> idea? Perhaps a more flexible bond would be better allowing the boards
>> a little bit of movement.
>> (The screed was layed last year with dpc and insulation, no likelihood
>> of damp problems).
>> Thanks for any advice.
>
> Most new houses that use this idea have polystyrene sheet - perhaps 2"
> thick or so - between concrete and chipboard. But I'd guess that would
> raise the floor height too much. Not sure why you want to do this though -
> chipboard won't add any 'bounce' to the floor.
>
Leave about 1/4" gap all round at the edges.
As above, I cant see the point meself..
If the screed is insulated, lay laminate, carpet or tiles or real wood
straight over the sealed concrete (PVA etc). If its not, construct a
framed floor above and fill with insulation..
PeterCB
wrote:
>
> Lay it fully floating but glued together on a thin polyethylene foam.
> Leave about 1/4" gap all round at the edges.
>
> As above, I cant see the point meself..
Load spreading - as in my note above the screed is only a couple of
inches thick over the celotex block so I'm not happy about putting
heavy machinery directly onto the screed, I would be worried about it
cracking.
I suppose the best thing would be to dig up the screed and the celotex
and just put down solid concrete under the machines.
>
> If the screed is insulated, lay laminate, carpet or tiles or real wood
> straight over the sealed concrete (PVA etc).
This is my new workshop, I'm not planning on having any other floor
covering, moisture resistant high density chipboard will do me nicely.
I have non-slip industrial mats in the main areas.
PeterCB
>
> Most new houses that use this idea have polystyrene sheet - perhaps 2"
> thick or so - between concrete and chipboard. But I'd guess that would
> raise the floor height too much. Not sure why you want to do this though -
> chipboard won't add any 'bounce' to the floor.
The bounce I am worried about would occur if the screed is higher at
the edges than the middle, or has hollow spots, or if the boards
decide to bow upwards, that's why I was thinking it would be best to
bond the boards to the concrete. I guess I'll lay the boards dry and
see how it feels.
Dave Plowman (News)
<4d6a9902-8715-4bb1...@g19g2000vbi.googlegroups.com>,
Seems it's a workshop? I'd be inclined to level the screed and use a
decent vinyl for the surface. Can't really see the point in nasty
chipboard.
--
*Happiness is seeing your mother-in-law on a milk carton
The Natural Philosopher
> On 19 May, 17:15, The Natural Philosopher <t...@invalid.invalid>
> wrote:
>> Lay it fully floating but glued together on a thin polyethylene foam.
>> Leave about 1/4" gap all round at the edges.
>>
>> As above, I cant see the point meself..
>
> Load spreading - as in my note above the screed is only a couple of
> inches thick over the celotex block so I'm not happy about putting
> heavy machinery directly onto the screed, I would be worried about it
> cracking.
> I suppose the best thing would be to dig up the screed and the celotex
> and just put down solid concrete under the machines.
>
I take it there is no rebar in the screed?
>> If the screed is insulated, lay laminate, carpet or tiles or real wood
>> straight over the sealed concrete (PVA etc).
>
> This is my new workshop, I'm not planning on having any other floor
> covering, moisture resistant high density chipboard will do me nicely.
> I have non-slip industrial mats in the main areas.
>
>
Id have painted the screed meself..jolly good finish is floor paint..
PeterCB
> PeterCB wrote:
>> On 19 May, 17:15, The Natural Philosopher <t...@invalid.invalid>
>> wrote:
>>> Lay it fully floating but glued together on a thin polyethylene foam.
>>> Leave about 1/4" gap all round at the edges.
>>>
>>> As above, I cant see the point meself..
>>
>> Load spreading - as in my note above the screed is only a couple of
>> inches thick over the celotex block so I'm not happy about putting
>> heavy machinery directly onto the screed, I would be worried about it
>> cracking.
>> I suppose the best thing would be to dig up the screed and the celotex
>> and just put down solid concrete under the machines.
>>
> ah industrial. Hmm.
> I take it there is no rebar in the screed?
Well looking at the pictures again, it seems they did put some wire mesh
in, but not exactly what you'd consider reinforcement.
There's a couple of pictures here:
http://www.pandasys.co.uk/pics/floor1.jpg
http://www.pandasys.co.uk/pics/floor2.jpg
I don't know how strong that celotex is, but I don't feel comfortable
about its ability to support heavy machinery with only a couple of
inches of screed over it.
Matty F
> The Natural Philosopher wrote:
> > PeterCB wrote:
> >> On 19 May, 17:15, The Natural Philosopher <t...@invalid.invalid>
> >> wrote:
> >>> Lay it fully floating but glued together on a thin polyethylene foam.
> >>> Leave about 1/4" gap all round at the edges.
>
> >>> As above, I cant see the point meself..
>
> >> Load spreading - as in my note above the screed is only a couple of
> >> inches thick over the celotex block so I'm not happy about putting
> >> heavy machinery directly onto the screed, I would be worried about it
> >> cracking.
> >> I suppose the best thing would be to dig up the screed and the celotex
> >> and just put down solid concrete under the machines.
>
> > ah industrial. Hmm.
> > I take it there is no rebar in the screed?
>
> Well looking at the pictures again, it seems they did put some wire mesh
> in, but not exactly what you'd consider reinforcement.
>
> I don't know how strong that celotex is, but I don't feel comfortable
> about its ability to support heavy machinery with only a couple of
> inches of screed over it.
Why not just put some thick plywood under the heavy machinery, and
paint the rest of the floor.
The Natural Philosopher
well you can drive over celotex without compressing it much.
The mesh is where it should be.
How heavy are these things? a couple of tons?
Surely not, in a 'domestic' room.
PeterCB
Well if that's the case then I probably have no need to worry, I
didn't think to feel how solid the celotext was before they covered
it.
However, now I have another concern - looking at that mesh, it appears
it will have stopped the screed from filling in the gaps between the
celotex, so whilst the screed over the celotex will be strong, I have
large pockets of air in the floor covered by a bit of mesh and a
couple of inches of concrete - or maybe they lifted the mesh and
filled the gaps first.
>
> The mesh is where it should be.
>
> How heavy are these things? a couple of tons?
lathe 450kg, mill 300kg
> Surely not, in a 'domestic' room.
it's semi-domestic, it's accessible from the house, but it's more like
an extension to the garage.
Franko
"PeterCB" <pe...@pandasys.co.uk> wrote in message
news:15530803-7d53-40d4...@r13g2000vbr.googlegroups.com...
Why such large gaps in the celotex ?
The Natural Philosopher
> However, now I have another concern - looking at that mesh, it appears
> it will have stopped the screed from filling in the gaps between the
> celotex, so whilst the screed over the celotex will be strong, I have
> large pockets of air in the floor covered by a bit of mesh and a
> couple of inches of concrete - or maybe they lifted the mesh and
> filled the gaps first.
>
Again the mesh SHOULD strengthen the floor to the point where its a sel
supporting raft. OK its not pretensioned, but its close.
>> The mesh is where it should be.
>>
>> How heavy are these things? a couple of tons?
>
> lathe 450kg, mill 300kg
>
So about the same as a bath totally full of water..that's really not
that massive.
>> Surely not, in a 'domestic' room.
>
> it's semi-domestic, it's accessible from the house, but it's more like
> an extension to the garage.
AAh..
bi...@rhinocad.co.uk
I have a new 25m2 workshop built over a block and beam floor suspended on engineering block and brick foundation walls.
The floor I asked for was a poured concrete floor but the builder offered me a 'just as good' dry screed. The screed is 75mm thick.Needless to say the floor is crumbly and unsatisfactory. I want to bolt wood working machines to the floor to prevent the consequences of an accident should the machines topple over. I tried fixing a 65mm anchor bolt into the floor and lifting it with a crow bar. The screed structure broke away as I suspected.
Short of digging it up and relaying it with concrete I am considering using a thick layer tile adhesive to bond a 22mm t&G chipboard floor to the screed. There are tile adhesives that will fill uneven surfaces and bond onto concrete floors and chipboard floors. The Chipboard would be glued along the joints to form a large single panel.
I am hoping that with a good bond the adhesion will cause the loading from any fixing bolt to spread in the screed and the screeds face to be supported by the chipboard over it.
I have pretty much decided to do this and hope this fixes my problem and might provide some insight into answering the original post.
Tim Watts
> I have a similar problem and although not identical, my thoughts on
> the subject may generate a solution.
>
> I have a new 25m2 workshop built over a block and beam floor
> suspended on engineering block and brick foundation walls.
>
> The floor I asked for was a poured concrete floor but the builder
> offered me a 'just as good' dry screed. The screed is 75mm
> thick.Needless to say the floor is crumbly and unsatisfactory. I want
> to bolt wood working machines to the floor to prevent the
> consequences of an accident should the machines topple over. I tried
> fixing a 65mm anchor bolt into the floor and lifting it with a crow
> bar. The screed structure broke away as I suspected.
>
Even screed should be pretty solid once fully cured (a very few weeks) -
so not only has he not done what was specified, he's not done it
properly either.
Tim Lamb
<tw_u...@dionic.net> writes
building inspector would accept.
Architects here, (Herts. chalk, clay or gravel) tend to specify B+B
knowing the builder will try to convince BC to allow hardcore plus
oversite concrete.
--
Tim Lamb
tabb...@gmail.com
For the rest of the floor, pouring well diluted glue into it may prove fine.
The OP was in 2009, no answer to that is needed.
NT