Storey and half dormer insulation

Pious14

5 year old house. All external walls have kingspan and insulated plasterboard. All grand. However parts of the house are cold and especially upstairs is hard to hold heat. The attic insulated with kingspan and rock wool.

However on closer inspection of the attic I have noticed the following:

1) attic knee wall - where cavity block and roof meets at both gable ends. The top of this is open to the cold air in the attic meaning the cold air is going down the cavity walls throughout the house. I assume this is causing problems for heat retention.

2) the roof slope dormer. Only half the dormer is insulated. The slope which can be accessed from the attic. The other half of the slope appears to only have kingspan with no rock wool. When I look down from the attic I can see the gap in the fascia. I assume this is also causing heat loss.

Are these causing my heat loss problems and what are my options?

BryanF

Air-tightness is very difficult to achieve in an existing dormer.

Results will depend on how much disruption your willing to endure

Metric Tensor

Also one thing to note is that the rafters of the roof need to be ventilated. So it's not necessarily wrong for you to be able to see the soffit from the "upper attic"

In most cases there should be a 50mm gap between the underside of the roofing felt and he insulation between the rafters.

You are on the right track looking for draughts though - find and seal up places where the warm upstairs air escapes into the cold attic. (You should still have your wall vents open of course)

Pious14

Thanks-do you think the open cavity gable end walls where the cold air from the attic is getting in is a big problem?

There is also an external vent but was never used internally (if that makes sense) as the room was not used for a fire. Therefore there is no internal vent but I assume the cold air from the external vent is going somewhere. Would it be worth blocking this also?

Metric Tensor

There should be an external vent in every habitable room regardless of whether there is a fire in it or not.

I don't quite follow what you are describing about the gable walls. Is there insulation in the walls? Does the wall insulation stop at ceiling level? If so - what type/thickness of insulation is used?

denismc

I have a bathroom that was always cold and so I recently had an energy survey done of the whole house.
The results were not what I expected, the overall insulation is ok but my air tightness was terrible, especially the cold bathroom.
I have lots of spotlights and pipes going through walls that were never sealed properly.
In one sense this is good as I don't have to upgrade the insulation but sealing all the leaks is going to take time but this is something I can do myself.

The energy survey was 400 euro which may seem like a lot but it will safe me doing a lot of expensive and unecessary alterations, so maybe it maybe worth doing something similar in your case.

Metric Tensor

Spot on denismc - downlighters are a particular problem!

Very hard to fix AT peoblems completely in an existing house but some steps can be fairly easy. All time consuming in the extreme though!

Pious14

Metric Tensor wrote: »

There should be an external vent in every habitable room regardless of whether there is a fire in it or not.

I don't quite follow what you are describing about the gable walls. Is there insulation in the walls? Does the wall insulation stop at ceiling level? If so - what type/thickness of insulation is used?

Ya there is insulation in the gable end. So basically in the attic you can see down the wall - ie between blocks. So there’s the the exterior block, gap, insulation, interior block. The gap here is exposed to the cold air in the attack. Is that ok or is it causing problems for cold air around external walls?

Pious14

Pious14 wrote: »

Ya there is insulation in the gable end. So basically in the attic you can see down the wall - ie between blocks. So there’s the the exterior block, gap, insulation, interior block. The gap here is exposed to the cold air in the attack. Is that ok or is it causing problems for cold air around external walls?

Here are some pics