What is the minimum R value of the insulation needed under a radiant slab application?
In warm climates, a minimum of R-5 is recommended below the slab; R-10 in cold climates. Also, make sure that you insulate the slab edge as that’s where the heat loss from a slab is greatest. Some people use twice the R-value at the slab edge as they do under the slab.
What type of insulation can be used to make radiant heat work more efficiently?
The best insulation for radiant floor heat is sheet foam insulation. These sheets are the most common type of insulation used when installing radiant heat on a slab floor.
How much insulation do I need under a slab?
A slab may be insulated on the entire bottom side, but if it is poured up against a foundation wall that is not insulated, the heat will travel up the wall and to the outside just like drafting up a chimney. A 4″ high, 3/4″ EPS insulation between the slab and the wall is money well spent.
Do you need to insulate under floor heating?
Why is insulation important for underfloor heating? Insulation is a crucial consideration for UFH. Ideally there should be suitable insulation below the underfloor heating pipe to resist the heat going downwards. As you would expect, you need as much heat as possible to flow upwards and into the room.
How do you insulate under radiant floor heating?
Staple down: If the radiant floor heating is done via staple down on top of the plywood subfloor or deck and the tube is poured in a cementitious material, you can use unfaced insulation. Push the insulation tightly against the bottom of the subfloor. Don’t compress the insulation or its net R-value will be affected.
How thick should slab insulation be?
A 50mm thick layer of proprietary floor slab insulation (e.g. 50mm Kingspan, Celotex or similar) is usually enough to reach and maintain the target U value but this should be checked with an architect first. Insulation sheets should be laid tightly together with the joints staggered to avoid movement.
Should you insulate under concrete slab?
To ensure that the foundation of your home isn’t a major source of heat loss, you should install rigid insulation before pouring concrete. Doing this protects the concrete from moisture as well as keeps heat inside the home and is required by many modern building codes.
How effective is under slab insulation?
Under slab insulation improves the thermal efficiency of the property by adding thermal resistance to the underside of the concrete slab on which the property is built. The slab is made from concrete which is poured on prepared and compacted earth and then reinforced for durability and longevity.
Does PEX need to be insulated under a slab?
You’d install PEX without sheath inside the slab for underfloor heating only. Otherwise it should be sheathed to allow it to comfortably expand depending on temperature variations, it also makes it possible to change the pipe if it bursts due to freezing, or bad quality pipe for example.
How do you insulate an existing concrete slab?
Step by step insulation of existing concrete slab
- Prepare the insulating floor. Remove dirt to fully expose the edges of the existing slab.
- Measure the distance between the slab.
- Install vapor barrier.
- Install the rigid foam.
- Install plywood panels.
- Install Threshold/Transitions.
- Finish the flooring material.