Under floor heating

[Tractor Tim]

I've done a few houses and cottages/ office by putting insulation in then using the reinforcing mesh to fasten the pipe to in the middle of the slab this helps to get it to respond to but you still get a good thermal store. My main concern would be the imposed load on the slab and then on the insulation if you were jacking up something with a bit of weight

 

[Optimus]

Not sure if it would work or not. I have limestone paving slabs in my house. Think their 22mm thick maybe more.they get pretty warm do take a while to heat up.

Also when it snows or is icy.where the underground heating pipes come across my drive into the house.the snow and ice melts where the pipes run below.there at least 3ft down.so your concrete might warm up if its on all the time.

 

[Smith31]

Underfloor heating will only work efficiently if the whole building is insulated and air tight, if doors are left open the heat will be lost. Heat will escape through steel doors, furthermore you will need ventilation for allowing exhaust gasses to escape, which will allow heat to escape.

It will cost a small fortune to heat a full floor, your best bet is lay 150mm kingspan below the concrete this will prevent the floor from becoming too cold and is 100% maintenance free.

 

[Hilly]

https://www.uponor.com/en-gb/products/special-applications/magna-industrial-floor-heating

Thats the kiddie ! Cheers

 

[Wisconsonian]

Oh my! This forum is great for different information, but this thread shows the dark side of different information, lots of bad information.

In the US, our houses rarely have heated floors, but farm shops are a very common place to see heated floors. ALL of this is as dead simple as you want it to be. It's been done to death in the US. The popular view is to use high density (25PSI rating) extruded polystyrene insulation under the concrete slab, usually 2", often less, rarely more. Then the tubing is usually fastened to the foam insulation so it ends up near the bottom of the slab. Better for the tubing to be near the surface, or at least in the center fastened to the steel, but it makes little difference in the scheme of things. Concrete is poured in one step, we don't do layers.

Google says the average temperature in Scotland is 8 C /46 F, so insulation under the slab is optional if you can use a coarse aggregate under the slab, and there is no ground water movement under the slab, the interior will be kept at 55-60 F, and the rest of the building will be well insulated including the edge of the slab. If you can insulate 4' down and 4' in with 2" of foam, then the heat from the slab has such a long distance to go to reach the outside that the heat loss through the floor will be insignificant.

If this site is on a generator, then a heat exchanger off the coolant is easy, after the thermostat for the good of the engine, or if you have another use for hot water, a heat exchanger off the exhaust will work too.

Much less critical if you have free heat, but for future proofing the shop, use as big diameter tubing and short of loops as practical. Here a 500' roll of 1/2 pex will be made into two 250' loops, three 166' loops is much better. 5/8" or 3/4" might make sense, depending. Longer loops will work fine with bigger diameter. If the loops are done right, the system could run on ground source heat pump, solar thermal or any other heat source in the future, and work better right from the start with whatever heat source you use.

 

[bobk]

That's the key to any heating , how cheap is your heat source , kero isn't a good option at the moment

I'd be putting a biomass boiler in and heating the whole shebang with it .

 

[Hilly]

Oh my! This forum is great for different information, but this thread shows the dark side of different information, lots of bad information.

In the US, our houses rarely have heated floors, but farm shops are a very common place to see heated floors. ALL of this is as dead simple as you want it to be. It's been done to death in the US. The popular view is to use high density (25PSI rating) extruded polystyrene insulation under the concrete slab, usually 2", often less, rarely more. Then the tubing is usually fastened to the foam insulation so it ends up near the bottom of the slab. Better for the tubing to be near the surface, or at least in the center fastened to the steel, but it makes little difference in the scheme of things. Concrete is poured in one step, we don't do layers.

Google says the average temperature in Scotland is 8 C /46 F, so insulation under the slab is optional if you can use a coarse aggregate under the slab, and there is no ground water movement under the slab, the interior will be kept at 55-60 F, and the rest of the building will be well insulated including the edge of the slab. If you can insulate 4' down and 4' in with 2" of foam, then the heat from the slab has such a long distance to go to reach the outside that the heat loss through the floor will be insignificant.

If this site is on a generator, then a heat exchanger off the coolant is easy, after the thermostat for the good of the engine, or if you have another use for hot water, a heat exchanger off the exhaust will work too.

Much less critical if you have free heat, but for future proofing the shop, use as big diameter tubing and short of loops as practical. Here a 500' roll of 1/2 pex will be made into two 250' loops, three 166' loops is much better. 5/8" or 3/4" might make sense, depending. Longer loops will work fine with bigger diameter. If the loops are done right, the system could run on ground source heat pump, solar thermal or any other heat source in the future, and work better right from the start with whatever heat source you use.

Ah wow thanks thats the kknd of info im looking for !! Brilliant thankyou for taking the time to type all that information ! Good to know my gut feeling it will work is right .

 

[Hilly]

That's the key to any heating , how cheap is your heat source , kero isn't a good option at the moment

I'd be putting a biomass boiler in and heating the whole shebang with it .

But what will i burn on bionmass ?

 

[bobk]

But what will i burn on bionmass ?

Anything , wood, straw , miscanthus

 

[steveR]

Insulated floor is a given.

Install acouple gas or kero blown space heaters to heat the workshop

Or Infrared?

 

[Wisconsonian]

If you're running a diesel generator already, a quick estimate is 1/3 of the fuel goes into electricity, 1/3 goes into the coolant, and 1/3 goes out the exhaust, so you have an easy 1/3 of the gallons per hour burned to use from the coolant, and much more difficult 1/6 total (half of the third in the exhaust) if you want to go after the exhaust heat. Assuming the generator is running during the day, and off at night, the heat sink of the slab and base will keep the shop warm enough overnight, and weekends.

yes, it will work, it will work very well if done close enough, it's done all the time. I can find some reliable sites if you want to read more.

 

[Hilly]

If you're running a diesel generator already, a quick estimate is 1/3 of the fuel goes into electricity, 1/3 goes into the coolant, and 1/3 goes out the exhaust, so you have an easy 1/3 of the gallons per hour burned to use from the coolant, and much more difficult 1/6 total (half of the third in the exhaust) if you want to go after the exhaust heat. Assuming the generator is running during the day, and off at night, the heat sink of the slab and base will keep the shop warm enough overnight, and weekends.

yes, it will work, it will work very well if done close enough, it's done all the time. I can find some reliable sites if you want to read more.

If the generator running say 8hrs a day would keep the concrete floor warm all id need is an electric water heater .

 

[bobk]

No

 

[Hilly]

No

Explain ?

 

[bobk]

Explain ?

Under floor heating runs 24 hours a day , thermostat decides when

 

[Hilly]

Under floor heating runs 24 hours a day , thermostat decides when

Flat out for 8hrs off for 16 thermostat this is redneck country not the shires

 

[bobk]

Flat out for 8hrs off for 16 thermostat this is redneck country not the shires

Clearly

 

[br jones]

Flat out for 8hrs off for 16 thermostat this is redneck country not the shires

no point in having it ,your using more fuel ,ufh is better left on at all times,

 

[tepapa]

Is the midden near the workshop? Run insulated pipes they use in ground source to the midden and collect the heat from the muck, run it back to the workshop.

 

[Hilly]

no point in having it ,your using more fuel ,ufh is better left on at all times,

The generator is on for other purposes .