Insulating first floor concrete workshop floor

[brewdexta]

My workshop is on the first floor, it is made of concrete poured into Kingspan Multideck, i.e. a corrugated steel pan with rebar and mesh in it and about 5" concrete like this.

The surface is relatively smooth but not like a babies bum, we poured it in winter up in the Pennines before the sides and roof were on. We did have big floats but of course it rained. It is painted with cheap floor paint that has seen better days.

The walls and roof are 50mm Kingspan insulated panels and if all goes well, the workshop will be heated soon. Floor area is 20m x 6m so need to get it right!

As the floor is a bit scabby and uninsulated and I don't fancy scrabbling the old paint off to put on epoxy, I was wondering if this idea is good or barking.

Put down Kingspan/cellotex type insulation, somewhere between 25 and 30mm, then cover it with 22mm moisture resistant chipboard T&G flooring or OSB or similar. Anywhere with point loads like lathe, bench or mill feet will have steel plates underneath the feet to spread the load. I can raise the steel workshop door about 30mm and it has a 20mm threshold so can get away with raising the floor by about 50mm, I haven't measured it yet.

The floor would then be covered with some kind of laminate or hard-wearing industrial plastic, maybe like this if I can find some sensibly priced, I have done before when we owned a retail shop.

Will use some kind of weld spatter resistant flooring near the welding bench. Probably chequer plate plus put some sheets of hardboard or similar and/or screens around the periphery if doing something big. I don't do a lot of welding so not too much of a pain.

Cheers
Andy

 

[gaz1]

id consider it as a thermal store if its designed like your pic

warm the concrete up using piping underneath it sealed so it has to go upwards against the concrete

 

[addjunkie]

You could insulate the underside....then use the wood or rubber over the top.
My house is concrete, kingspan, heating pipes the a 70 mm concrete self leveling screed.

Though your suggestion above will work, you will end up with a bittly floor, steel, and wood, etc wont beable to move big heavy stuff around.
The wood and rubber would actually insulate a little.

A workshop that size will cost afortune to heat unless of course you are on comercial RHI, in which case heat away and dont waste your money on insulation.

 

[Shox Dr]

Machinemart sell button floor. Used to be very cheap.

 

[slimjim]

What you propose will work, but it's not ideal, can you not insulate the ceiling below?

 

[brewdexta]

Thanks for the comments guys. I have wet underfloor heating in the house. Both in the structural slab and in a screed depending on how far I could dig before hitting rock. I'm a big fan of it but trying to get it in close contact with the corrugated underside and then insulate would be a right pain. I was considering spraying the underneath with insulating foam which would help insulation and stop condensation on the underside, especially when I'm brewing downstairs.

Apart from the shabby paint, working on concrete is hard on the bones so was hoping to fix both issues at the same time.

I'm not on commercial RHI. Current heating plan is a 15kw pellet boiler and fan coil units. I don't intend to heat it to 18c, too hot, probably 10 or 12 when working in there and less when away to keep the condensation off the machinery.

Cheers
Andy

 

[octo0072000]

insulate from underneath some cheap carpet above over cardboard for the bones can be changed at little cost when worn out etc

 

[slimjim]

Thanks for the comments guys. I have wet underfloor heating in the house. Both in the structural slab and in a screed depending on how far I could dig before hitting rock. I'm a big fan of it but trying to get it in close contact with the corrugated underside and then insulate would be a right pain. I was considering spraying the underneath with insulating foam which would help insulation and stop condensation on the underside, especially when I'm brewing downstairs.

Apart from the shabby paint, working on concrete is hard on the bones so was hoping to fix both issues at the same time.

I'm not on commercial RHI. Current heating plan is a 15kw pellet boiler and fan coil units. I don't intend to heat it to 18c, too hot, probably 10 or 12 when working in there and less when away to keep the condensation off the machinery.

Cheers
Andy

Well you could insulate the ceiling below, then use the rubber matting on the floor,

With the insulation, then it should be easy to achieve 12-14 degrees inside, with not a great deal of heat input,

 

[brewdexta]

Food for thought, that would lower costs a bit.

I've heard some horror stories about spray on foam insulation companies, I guess I need to do some research.

 

[slimjim]

Food for thought, that would lower costs a bit.

I've heard some horror stories about spray on foam insulation companies, I guess I need to do some research.

You can DIY, it's not cheap though,

You could fix celotex to the ceiling using plasterboard fixing foam, or cartridge glue, then gluing whatever ceiling finish to the celotex, or use plasterboard celotex board

 

[Shox Dr]

Food for thought, that would lower costs a bit.

I've heard some horror stories about spray on foam insulation companies, I guess I need to do some research.

I’d certainly look into it Andy, it would solve two problems in one go.

 

[knighty]

is the room underneath heated ?

 

[Burdekin]

What is below? Is someone heating under you and if so then don't insulate under the floor. Heat only goes from hot to cold direction. Insulating above would give most benefit to hearing the air. The concrete will take a lot to heat up so if you just turn the heating on when you get there will take a while to heat up, insulating above the floor will take less time to heat the air in the workshop.

 

[addjunkie]

Awful job, but just use normal rolls of insulation from below held in place by wood, plaster board, chicken wire what ever. Be cheapest option too.

Though cheapest option would likley be thermal coveralls, good woolly hat and knee pads.

 

[brewdexta]

Beneath the workshop is my barn and two semi-underground cellars, one with a micro-brewery, the other full of old tractor bits and garden machinery. The barn is unheated, it is split by steel columns into four 5m long by 6m wide bays. The bay nearest the cellars is enclosed by 50mm metal clad kingspan panels and eventually will be partitioned off from the other 3 bays. These have Yorkshire boarding on them so are ventilated. The boiler will go in the first bay with the paneling which means I will have one warmish area downstairs. The upstairs will be heated by fan coil units fed from the boiler.

The following photo from construction in 2008 shows the stone part nearest that forms the cellars with my office above, then the 20m x 6m steel frame part, the workshop is above the barn below. You can see the first two bays have the multideck in place.

And now with Yorkshire boarding covering both insulated panels and barn. The office is super insulated and has electric underfloor heating

Spray on foam under the floor and rubber matting on top seems like a plan. I've got hat and gloves on now and I'm changing bearings in my wood lathe and its not what I would call enjoyable, not because they are being a pig but because it is bloody freezing.

I've decided that as life is not a rehearsal and I don't believe in an afterlife and there are no pockets in a shroud I shall insulate it, heat it and enjoy it

Cheers
Andy

 

[GW8IZR]

I've decided that as life is not a rehearsal and I don't believe in an afterlife and there are no pockets in a shroud I shall insulate it, heat it and enjoy it

Cheers
Andy

That is exactly my outlook on life!

 

[gaz1]

you have half this as it stands



a rocket stove or a simple downdraft stove would create the same effect

 

[Woody.v8]

Another solution, You could just rub deep heat on your feet and bingo , everywhere you stand will feel toasty

 

[Shox Dr]

Too right, I bought a cheap bathroom halogen IR heater from wicks, you can run it through a dimmer. And doesnt emit red light.

Instant heat

 

[brewdexta]

you have half this as it stands

View attachment 125940

a rocket stove or a simple downdraft stove would create the same effect

Not quite Gaz, that looks like a Roman hypocaust

I have a steel framed structure holding up a concrete floor 3m up in the air with a corrugated underside. Underneath the slab is intersected by multiple beams in a grid. Making that into duct work for heating would be nice but a pig to do!

I also want a heating system that is controllable and will heat unattended, with a bit of luck I will be getting one of these pellet boilers and heat coil units second hand.

A bit posh I know but I have some post retirement plans for the barn/workshop to top up the pension and heat will be essential. I may start looking if there are any agricultural diversification grants knocking about I can take advantage of.

Cheers
Andy