Improving a workshop (ex-garage) - floor and doors

[noth...@aolbin.com]

Currently the floor is a concrete slab so I'm wondering about using ply
or OSB to create a floating floor over 50mm insulation boards, but I've
no idea how well the foam would cope with the weight of machines, drill
press, lathe, etcetera sat on it. Another option is to forget the
insulation and sit the board on the concrete (there's already a DPM), or
to use rubber mat (roll or interlocking).
What have others done?

There are 2 roller shutter doors so I plan to build an insulated stud
wall inside one of them but want to retain access to t'other so am
thinking of a pair of some kind of insulated plugs that, when not
wanted, will slide into the void created between the other door and the
stud. Any ideas?

[Jeff Layman]

On 22/11/2023 20:36, noth...@aolbin.com wrote:
> Currently the floor is a concrete slab so I'm wondering about using ply
> or OSB to create a floating floor over 50mm insulation boards, but I've
> no idea how well the foam would cope with the weight of machines, drill
> press, lathe, etcetera sat on it. Another option is to forget the
> insulation and sit the board on the concrete (there's already a DPM), or
> to use rubber mat (roll or interlocking).
> What have others done?

When we moved in we found that the back half of the garage had been
turned into a dog grooming parlour. The floor was 50mm expanded
polystyrene over the original concrete, then covered with T&G flooring.
To get the car in the garage, I took down the dividing wooden stud wall,
and parked the front of the car on the parlour floor. I've been doing it
for 11 years, and the polystyrene is still at 50 mm.

> There are 2 roller shutter doors so I plan to build an insulated stud
> wall inside one of them but want to retain access to t'other so am
> thinking of a pair of some kind of insulated plugs that, when not
> wanted, will slide into the void created between the other door and the
> stud. Any ideas?

--

Jeff

[SteveW]

On 22/11/2023 20:36, noth...@aolbin.com wrote:

> Currently the floor is a concrete slab so I'm wondering about using ply
> or OSB to create a floating floor over 50mm insulation boards, but I've
> no idea how well the foam would cope with the weight of machines, drill
> press, lathe, etcetera sat on it. Another option is to forget the
> insulation and sit the board on the concrete (there's already a DPM), or
> to use rubber mat (roll or interlocking).
> What have others done?

Use insulation and board, but leave holes where the machines are to go
and then fill those holes to floor level with concrete?

[noth...@aolbin.com]

On 22/11/2023 21:55, Jeff Layman wrote:
> On 22/11/2023 20:36, noth...@aolbin.com wrote:
>> Currently the floor is a concrete slab so I'm wondering about using ply
>> or OSB to create a floating floor over 50mm insulation boards, but I've
>> no idea how well the foam would cope with the weight of machines, drill
>> press, lathe, etcetera sat on it. Another option is to forget the
>> insulation and sit the board on the concrete (there's already a DPM), or
>> to use rubber mat (roll or interlocking).
>> What have others done?
>
> When we moved in we found that the back half of the garage had been
> turned into a dog grooming parlour. The floor was 50mm expanded
> polystyrene over the original concrete, then covered with T&G flooring.
> To get the car in the garage, I took down the dividing wooden stud wall,
> and parked the front of the car on the parlour floor. I've been doing it
> for 11 years, and the polystyrene is still at 50 mm.

Thanks, that's interesting. Quite a while ago I did some work in a
kitchen where the T&G floor was just sat on insulation board, but it had
sagged in the middle, hence my caution.

[noth...@aolbin.com]

Yes, I'd wondered about that but some of the machines are on castors and
occasionally need to be moved a few feet. I guess the pads could be
larger than needed, but I rearrange things from time-to-time and
wouldn't want to be tied.

[Jeff Layman]

On 22/11/2023 23:10, noth...@aolbin.com wrote:
> On 22/11/2023 21:55, Jeff Layman wrote:
>> On 22/11/2023 20:36, noth...@aolbin.com wrote:
>>> Currently the floor is a concrete slab so I'm wondering about using ply
>>> or OSB to create a floating floor over 50mm insulation boards, but I've
>>> no idea how well the foam would cope with the weight of machines, drill
>>> press, lathe, etcetera sat on it. Another option is to forget the
>>> insulation and sit the board on the concrete (there's already a DPM), or
>>> to use rubber mat (roll or interlocking).
>>> What have others done?
>>
>> When we moved in we found that the back half of the garage had been
>> turned into a dog grooming parlour. The floor was 50mm expanded
>> polystyrene over the original concrete, then covered with T&G flooring.
>> To get the car in the garage, I took down the dividing wooden stud wall,
>> and parked the front of the car on the parlour floor. I've been doing it
>> for 11 years, and the polystyrene is still at 50 mm.
> Thanks, that's interesting. Quite a while ago I did some work in a
> kitchen where the T&G floor was just sat on insulation board, but it had
> sagged in the middle, hence my caution.

I wonder why it had sagged (if it wasn't on concrete, perhaps whatever
it was on had sagged underneath!). I just checked, and the compressive
strength of EPS is at least 70kPa (around 10psi). Insulation board
should be double that. So although I can understand indentation from, eg
castors or narrow legs, I can't understand sagging over a larger area.
FWIW, I guess if I had put the car tyre directly on the EPS, then it
would almost certainly have crushed it (I reckon it works out at about
35psi), but the T&G would have spread that out over a much greater area.

--

Jeff

[Tricky Dicky]

When making my mancave I used 75mm PIR over the concrete floor and topped
it with 18mm chipboard T&G glued together with a PIR glue. Nothing has
moved or sagged despite at the moment it contains all the fixtures and
fittings for the bathroom refurb.

[RJH]

Does the insulation make much difference?

Of all the things I did at my last place, 50mm underfloor celotex seemed the
least effective. Difficult to tell objectively, but maybe 1-2C difference
between uninsulated (but carpet and thick underlay) and insulated. So I'm
wondering whether to bother at the new house.
--
Cheers, Rob, Sheffield UK

[John Rumm]

On 22/11/2023 20:36, noth...@aolbin.com wrote:

> Currently the floor is a concrete slab so I'm wondering about using ply
> or OSB to create a floating floor over 50mm insulation boards, but I've
> no idea how well the foam would cope with the weight of machines, drill
> press, lathe, etcetera sat on it. Another option is to forget the
> insulation and sit the board on the concrete (there's already a DPM), or
> to use rubber mat (roll or interlocking).
> What have others done?

Something like PIR boards under a decent thickness of sheet material to
spread the load, it surprisingly crush resistant. However If you wanted
a stiffer floor, then you could insulate and screed over it with 2" of
fibre reinforced concrete. (assuming you can cope with the loss of
headroom and the extra step in the floor)

> There are 2 roller shutter doors so I plan to build an insulated stud
> wall inside one of them but want to retain access to t'other so am
> thinking of a pair of some kind of insulated plugs that, when not
> wanted, will slide into the void created between the other door and the
> stud. Any ideas?

An inner sliding insulated door perhaps (the "door" being nothing more
than a lump of insulation board with a skin of wood product
encapsulating it well enough to allow it to be "hung")

--
Cheers,

John.

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[Tricky Dicky]

Dunno, but it seems a requirement in modern solid floors to insulate below
the concrete and I have seen it done in projects where out buildings are
converted into living places in those cases like mine the insulation is
installed above the concrete and a floating timber floor on top.

[noth...@aolbin.com]

On 23/11/2023 12:14, John Rumm wrote:
> On 22/11/2023 20:36, noth...@aolbin.com wrote:
>> Currently the floor is a concrete slab so I'm wondering about using
>> ply or OSB to create a floating floor over 50mm insulation boards, but
>> I've no idea how well the foam would cope with the weight of machines,
>> drill press, lathe, etcetera sat on it. Another option is to forget
>> the insulation and sit the board on the concrete (there's already a
>> DPM), or to use rubber mat (roll or interlocking).
>> What have others done?
>
> Something like PIR boards under a decent thickness of sheet material to
> spread the load, it surprisingly crush resistant. However If you wanted
> a stiffer floor, then you could insulate and screed over it with 2" of
> fibre reinforced concrete. (assuming you can cope with the loss of
> headroom and the extra step in the floor)

The height is about 2.7m so headroom isn't an issue, but I'd prefer not
to mess around with concrete because of having to empty the place and
then wait for the humidity levels to drop.

>
>> There are 2 roller shutter doors so I plan to build an insulated stud
>> wall inside one of them but want to retain access to t'other so am
>> thinking of a pair of some kind of insulated plugs that, when not
>> wanted, will slide into the void created between the other door and
>> the stud. Any ideas?
>
> An inner sliding insulated door perhaps (the "door" being nothing more
> than a lump of insulation board with a skin of wood product
> encapsulating it well enough to allow it to be "hung")

Yes, that's sort of what I had in mind but I can't think how to get them
to seal adequately when in position. I doubt that brush strips would
work well enough, and sliding rubber seals would be a pain to set-up and
maintain. Insulated bi-fold doors (closing onto seals) might be a better
option, but I'd prefer not to have to keep the door area clear.
Tricky!

[Vir Campestris]

On 22/11/2023 20:36, noth...@aolbin.com wrote:

> What have others done?

Beam and block floor. In the workshop and garage I just painted it; in
the office there's a layer of insulation, then a chipboard floor.

Andy

[RJH]

Yes, helped a mate with a living room solid floor - building regs required
50mm of celotex with (basically) the concrete slung on top. I can see that it
*should* make a difference. Just, anecdotally, didn't seem to.

Mine are suspended timber with easy access - so it would be easy, if only I
could convince myself it'd be worthwhile.

[Robin]

If you only need occasional access do you need anything as sophisticated
as brush strips or sliding seals? I have in mind just building another
stud wall in 2 or 3 sections in front of the second door but screwed to
one another and the studs either side; foam strip where they join to
keep the wind out; and coach screws to withstand better the repeated use
of impact driver to fit and remove.


--
Robin
reply-to address is (intended to be) valid

[Animal]

EPS/XPS is feeble stuff. PIR is tougher but I wouldn't put industrial machinery on it. 2 alternatives are wood with insulation between, putting the heavy machines on the wood. Another is lightweight concrete blocks, they insulate reasonably & withstand more load than PIR. Whether it's enough for a lathe depends.
Flooring sheet does spread load, but not very well. All kinds sag under load, loading the insulation under it.