Insulating Dormer Extension

[Deleted User]

Apologies if my thread is in the wrong part of the forum but it is to do with saving energy.

About 2.5 years ago I bought a top floor flat with dormer extensions. The extensions are so old there's no paperwork for them so I have no idea how well insulated they are, if at all. If it means anything the EPC rating when I bought my flat was D. The EPC suggests increasing loft insulation and the ol' energy saving lightbulbs.

There is a noticeable temperature gradient in the rooms of my flat as you walk into the Dormer extensions. However, I don't find my flat too cold to live in during the winter so maybe it's not that big a problem.

I have contacted Home Energy Scotland who have suggested improving the loft insulation (I think only the eaves are currently insulated.) and internal wall insulation. There are interest free loans available for the work and the Scottish government will contribute up to 25% of the cost. The loft insulation seems like an easy one but the internal wall insulation seems like a much more disruptive job especially since I have decorated a few rooms.

Does anyone have any experience of retrofitting internal wall insulation? Do you think it's even worth me bothering about?

The EPC gave no energy efficiency or environmental rating for my floors as there are other dwellings below me but my floors are cold. I was wanting to buy new carpets anyway since the ones in the flat were done when I moved in.

I should add that I don't see this as my forever home and would be looking to move again in 2020/2021.

Raxiel

Whoever did the EPC probably just ticked boxes in an excel form. Anything other than the most common construction usually stumps them.

My own home has a mansard roof that extends down over the first floor. The construction being Tile-Felt-Ratty old Rockwool (where it's not perished) - plasterboard.

I've looked into insulation options in the past, the blown cavity fill people won't touch it (risks knocking the tiles off). There are thermally insulated roof tiles available, but they are very expensive.

Ultimately the best option seems to be additional insulation on the inside (loosing room space), or stripping off the internal plaster, replacing the rockwool with celotex boards between the timbers (leaving an air gap), putting up a vapour barrier and reboarding+skimming.

Neither is really a job you want to do after decorating.

If it was just the dormers you may be able to get away with just sticking up some of that 'tinfoil bubble wrap' on the sides and having it skimmed over and re-painted.

Given your timescale, I'm not sure I'd bother with either though.

[Deleted User]

I think you are right and none of the options are really worthwhile given I don't see this as my forever home. Saying that I bet I end up being carried out this property in a box one day.

I shall spend my money on new carpets because I think they will give me the most pleasure. No point having a beautifully decorated room and threadbare carpets.

You are quite right, the EPC is nothing but a box ticking exercise. Money for old rope.

AnnaHind12

Have you considered externall wall insulation? My aunt had it done on her house through a company called EWI store and it has apparently worked wonders for her.

matelodave

Loft insulation is easy and reasonably cheap so worthwhile I'm not so sure about external cladding (unless someone else is paying for it).

You could do some heat loss calculations to see what proportion of your flat is taken up by the dormer(s) to see how much heat is actually lost and so estimate how much you might save off your heating bill.

In the end, whatever you do has to be cost effective. Spending £2k and saving £100 a year on your heating will take you 20 years to recoup the cost so not worth it IMHO. It would take even longer to payback if you have to take out a loan to pay for it as well

If the floor is cold, then get some carpet and decent underlay to insulate it, do as much draughtproofing as possible.

I refurbed my bungalow seven years ago and it's now got 400mm loft insulation, insulated cavity walls, double glazing, an airsource heatpump with underfloor heating and still only managed to get a D rating on the EPC (it was G before though). It would now cost several £1000's to try and push it up to C but I'd only save around £50 a year, so it's easy to get into the realms of diminishing returns, spending far more than you'll ever save.