Insulation

[AjohnwParticipant @ajohnw51620]

I parked all sorts of things including a land cruiser on a slab I laid when I lived with my parents a very long time ago. Done to "dads" instructions. It's a bit over 4" thick, 6ft something wide and probably 20ft long. Main instruction was not to disturb the under soil when digging it out. No polythene and no hard core. My parents left the premises over 15 years ago and when I drove past a year ago it's still in use. Normal concrete, what ever readymix supplied when asked to deliver. Just carefully tamped down with the edge of a plank.

I had a slab laid here. Doubt if I will ever put a decent big garage on it but some one might. I came across a black country lad with a jcb and they did it. I noticed him working carefully in some ones garden. Turned out his dad owned a fairly big company that did car parks and things like that. They dug out carefully and scraped level with the gradient I asked for. Polythene down, reinforcement raised up and the the concrete poured. Our current garage is a sort of extended outhouse up by the house so they laid a drive to that too. Some hardcore went in too via a tipper. I can't see how this helps at all if the under soil is loose. Something will sink or tilt etc.

After he had finished he came up with a smile on his face and said that if I ever wanted to do the same thing again I could hire a jcb with driver for around £110 a day at the time and the concrete suppliers can shutter up and lay the slab. It would have worked out at about 1/2 the price to a bit more. He also said that if I had hired the jcb from them and asked for a skilled driver they would have probably sent him.

I'm not complaining. I had been quoted a lot more. While he was at it he even pulled out a large pear tree and smashed the soil down with jcb.

John

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[Sam Longley 1Participant @samlongley1]

Posted by Tractor man on 22/11/2016 18:35:47:
Hi all.
My new sectional concrete workshop has been erected today and I am looking for anyone's experience of insulating such a structure to make it more livable in winter.
My thoughts are to line the steel roof with kingspan boards and similar with the walls. Then skin this with ply wood.
If anyone has any views or suggestions please let me know. Mick

I took some 25 * 50mm battens & lined them up with the joints in the concrete panels vertically. I loosened the joint bolts & wound some doubled up tying wire around one end of the bolts & round the battens then back round the other end of the bolt. Using steel fixers end cutters I tensioned the wire so much so that it cut into the batten. There were 4 bolts to each joint so each joint got 4 ties. I then cut 25mm celotex between each piece of batten. At windows I cut the battens & pinned them horizontally so the ends pinned to the verticals. At the door there were extra strong studs so i was able to screw the 25*50 batten. Having done this I pinned 4mm ply horizontally all round. I then cut some more 4ft * 8 ft ply in 2 ft strips * 8ft & pinned this round to cover the celotex to a height of 6 ft which protects it adequately. the celotex above this is exposed for about 150mm . I cut off cuts of celotex to fit double thickness into the eaves.

For the roof i placed 25 th celotex from the eaves to the wood purlins & one end was trapped at the eaves & at the purlin end I pinned some 12 * 12 batten to the side of the purlin to hold the celotex. Between purlin & ridge I did a similar method of fixing

For the garage door & glued 25mm celotex to the back of the door with recesses for the control gear but being 25 th it goes behind the lock bars ok & does not upset the balance of the garage door for opening

25 celotex is ample for a workshop & it warms up with a 2kw electric fan heater in 30-45 mins

I have no condensation problems. There is no insulation in the slab& it is not necessary. The slab is unreinforced 125mm concrete. The workshop is 22ft & 10 ft 3ins with cementous sheet roof. 2 windows, 1 up & over door & one metal side door. I had the extra height option to give me headroom inside

Edited By Sam Longley 1 on 05/12/2016 21:19:18

[MuzzerParticipant @muzzer]

Nigel – as I said, the mesh was only laid in the dining area as it would otherwise be left over. Not necessary really but why not? In both areas there were enough gaps for the concrete to grab the mesh and of course if a slab is going to collapse it will try to stretch the mesh, whether it's keyed to the concrete or not. On the face of it, the lower the mesh the better. It's 6" thick as it is, so the mesh may be a bit of overkill, even in the workshop area…..

Interestingly, the concrete was mixed 1 tonne at a time outside the house and the mixer lorry came complete with several men with wheelbarrows. There wasn't much chance of getting the lorry down the drive. Beats trying to estimate the total required and then finding you had over or underestimated the quantity by a few tonnes either way.

Murray

[Neil WyattModerator @neilwyatt]

Posted by Tractor man on 22/11/2016 18:35:47:
Hi all.
My new sectional concrete workshop has been erected today and I am looking for anyone's experience of insulating such a structure to make it more livable in winter.
My thoughts are to line the steel roof with kingspan boards and similar with the walls. Then skin this with ply wood.
If anyone has any views or suggestions please let me know. Mick

My approach was similar to Sams, battens spaced so that polystyrene fitted in the gaps between. Horizontal fixing for shelves and ring main wiring added, then a vapour membrane, then plasterboard, just taped & painted.

Floor is concrete so I put down treated 2×3's on strips of DPC, then a vapour membrane, then a floor of ODB which is much stronger than chipboard and more affordable than ply.

Ceiling was a fail, I didn't insulate just used hardboard and a vapour membrane. I wish I had insulated it and used plasterboard.

[Howard LewisParticipant @howardlewis46836]

My shop is wood, inside and out with 50mm glassfibre insulation.

Helped a friend insulate his sectional concrete shop. He used 50mm polystyrene sheets, with a vapour barrier between the insulatiion and the internal cladding. (sectional concrete buildings are prone to "sweating" he said) The steel roof trusses ( low pitched roof) were insulated, again, with polystyrenee sheet. He now has a nice cosy shop! The concrete floor is uninsulated, except by old carpeting.

Howard

[Sam Longley 1Participant @samlongley1]

I am sure forumites are aware but it has to be said :—-

If one is going to use polystyrene then one should be certain that it is fire resisting grade. Many of the light weight "large granule" white sheets are not. They are also less impact resistant. The fumes can be dangerous & in a workshop, fire must be considered a distinct possibility.

With Celotex etc the requirement for vapour barrier is not needed as the foil facing acts as such but the joints do need to be taped with aluminium foil

[Paul H 1Participant @paulh1]

Hi Tractorman,

Your proposal to use Kingspan is a good one, it works very well but get the thickest you can afford. The last time I used it for a similar use 90mm was available (15 years ago). Perhaps thicker is now available. You can frame out the building with wood or metal frame. Where I live the latter is cheaper and it is quick to erect. As the building is for a workshop it is better to line out with OSB or shuttering grade plywood. This means that you will have a head start for fixing storage units, benches, tool racks to the walls etc. Also mounting trunking for electrics is easier.

What Neil used on his floor is interesting, but I would add rigid polystyrene insulating boards between the battens (same thickness), for both insulation and strength. However floor construction does depend a bit on what type of machines you propose to put on it, Other contributors may have already done this and can give advice. I have always stuck to concrete and when starting from scratch, used polystyrene beneath the concrete and laid 6" of rebarred self levelling concrete.

Paul

[MuzzerParticipant @muzzer]

There are various manufacturers of polyurethane foam insulation. The stuff we are using in our extension is Recticel Eurothane (a pun on polyurethane, ahhh!) and it's available in thicknesses from 25mm to 160mm. It's not very expensive and seems to be easy to find. Celotex seems to be available in thicknesses 50-200mm. Kingspan also seems to be broadly similar. I'm not an expert on these products by any means but there seems to be quite a choice of suppliers.

[vintagengineerParticipant @vintagengineer]

Celotex or Kingspan is the best solution, even better if you can leave an air gap between the insulation and block work.

[mechman48Participant @mechman48]

I lined my garage with1" Celotex in between the 2" studding frame with a 1" air gap between it & the brickwork, then covered with 12mm OSB & painted white, with electrical trunking on top. the roof space was boarded with plasterboard on the underside of the roof trusses then on the top side covered with space blanket loft insulation, when it does get cold I have two small oil filled rads which I turn on before I go in, it usually gets up to approx 12 – 14* within 3/4 of an hour & have had it up to 18* within 1-1/4 hrs on a cold day, the roll panel door is covered in same Celotex panels as is the entry door… so plenty warm for me. There are a couple of pics in my album 'garage conversion'

​George.

[Michael MallesonParticipant @michaelmalleson22793]

Hi Mick. as you are probably aware, condensation is your biggest enemy. So, in the immortal words of Tony Blair, "insulate, insulate, insulate ; dehydrate, dehydrate, dehydrate. " Leave a small dehumidifier running all the time on a mid range setting and empty regularly. I haven't had a spot of rust in 10 years. Very cheap to run and being dry you will feel warmer with less heat.

Mike.

[Nigel McBurney 1Participant @nigelmcburney1]

Take some precautions to prevent vermin (mainly mice) getting into the insulation,before fitting insulation fill every crack and crevice with mortar or similar to prevent mice entering from outside,plus ensure that the door is a good fit.All electrics should be surface mounted ,if the wires have to go through an insulated wall or partition use a steel conduit through the wall or mice will chew it.

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