The insulation is Dritherm which is a woolly type. It says it's water proof but I can't imagine it sits on the foundations or a lean mix infill should there be one. If that's the case does anyone know there's a minimum clearance please?
Is there a minimum distance between foundations and the cavity insulation?
- Thread starter davidmiller
- Start date
No minimum distances. Check with the manufacturer.
The standard detail of cavity walls at ground level are a bit bizarre, and there are lots of different details on the internet - many contradictory.
In some cases, EPS or suchlike is specified below ground and up to DPC and then the quilt starts.
In practical terms, I would not want quilt to potentially stand in water collected in a cavity - minimum distance or not.
The standard detail of cavity walls at ground level are a bit bizarre, and there are lots of different details on the internet - many contradictory.
In some cases, EPS or suchlike is specified below ground and up to DPC and then the quilt starts.
In practical terms, I would not want quilt to potentially stand in water collected in a cavity - minimum distance or not.
Thanks, it doesn't seem to be an exact science does it.
I reckon I'll start insulation 100mm lower than internal floor level that way there's an overlap with the underfloor insulation. And that should leave about 1500mm clearance from the foundations for any water.
Last edited:
There is a concept of creating an insulation envelope so that floor, wall and roof insulation is continuous, to avoid or minimise thermal bridges or breaks to the internal rooms.
At floor level this could mean that cavity insulation goes down to the level of floor insulation, or that floor insulation is turned up to the level of where cavity insulation stops, or that insulating inner leaf blockwork performs the insulating function.
Some people may consider insulation bridging the DPC layer to be a bad thing, so detail the floors and inner leaf to deal with the insulating function.
Others may want insulation below ground level but then need to think about the cavity filling with water.
So there are several ways to meet a goal, and science - the migration and insulation of heat and moisture is involved. The problems occur when a designer chases one target and forgets about the implications.
The frost layer for external ground is typically about 250-300mm. So if you intend to insulate a wall then that depth is a target. And insulation in the cavity does not prevent a potential cold bridge of the internal wall leaf moving up past the DPC internally.
At floor level this could mean that cavity insulation goes down to the level of floor insulation, or that floor insulation is turned up to the level of where cavity insulation stops, or that insulating inner leaf blockwork performs the insulating function.
Some people may consider insulation bridging the DPC layer to be a bad thing, so detail the floors and inner leaf to deal with the insulating function.
Others may want insulation below ground level but then need to think about the cavity filling with water.
So there are several ways to meet a goal, and science - the migration and insulation of heat and moisture is involved. The problems occur when a designer chases one target and forgets about the implications.
The frost layer for external ground is typically about 250-300mm. So if you intend to insulate a wall then that depth is a target. And insulation in the cavity does not prevent a potential cold bridge of the internal wall leaf moving up past the DPC internally.
My take on is that if you include internal perimeter insulation at floor slab level, there isn't the need to dip the cavity insulation into the sub-DPC trough.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Similar threads
