insulation options for an older house

femalemonarchfemalecanine

My home was built mid 1930s, is two layers of brick but no cavity, and mostly roughcast on the outside. It's detached, but is so close to next door downstairs (about a 3-4 inch gap) that there seems no scope to do anything there. 

I recently had an extension downstairs on the side, which is obviously much better insulated and markedly warmer - it does in fact raise the temperature in the whole downstairs.
I get mould inside on any external wall that I put furniture or curtains against; it's quite a problem, I have loft insulation [it was done for free under a council or energy company scheme, and I intend to get it checked out soon to make sure it is ok or get it replaced], gas central heating and had the whole house double glazed best part of 15 years ago [which is still functioning fine, no misted panels or anything like that]. Getting that and new external doors halved my gas usage in one fell swoop!

I've heard that external insulation is good - but this was off a friend who had it council installed, and I own my home - but I'd not know where to start finding anyone to come and look to assess or quote [I'm in the West Mids]

Any advice  on any of this, or personal recommendations for products or trades would be gratefully received, I will respond, but I'm not on here every day, so I will say thank you very much in advance for any help.

FreeBear

External wall insulation (EWI) has advantages and disadvantages - You don't lose any internal floor space, and you get a nice clean rendered finish of your choice (including colour). On the downside, downpipes from gutters, bathrooms, toilets need to be moved, and window sills need extending. Detailing around the roof line and door/window openings is crucial so as to avoid cold spots and points where water can get down behind the insulation. If you have a bay window, the detailing around each side can look piggin' ugly.

Internal wall insulation (IWI) is another option. You lose floor space (typically 75mm) and every room needs redecorating afterwards. Unless floorboards are lifted, you have a cold spot under the floor that can be difficult to deal with. Toilets, bathrooms, and kitchens add to the headache of redecorating. And if the stairs are against an external wall, this will limit how much, if any insulation can be put on that wall. On the plus side, you get nice smooth walls ready to be decorated to your taste. Window & door reveals can be insulated much more effectively, but bay windows can still be problematic. You can also do one room at a time if the budget does not allow for the whole house to be done in one go.

With EWI, the house will take longer to heat up from cold, but the walls will act as a thermal store so won't go cold as quickly. With IWI, the rooms heat up quicker, but also cool down faster due to the lack of thermal mass - The energy consumption is very similar between EWI and IWI, so there is little to choose on that point.

Your loft insulation - Assuming fibreglass, will have a life span of 50 years or more. Current recommendation is 270-300mm, so it might be worth adding another layer if you have 200mm. Certainly no need to rip the old stuff out. Just don't get conned into having spray foam insulation put in under the tiles - It will cause problems when you come to sell, and there is growing (anecdotal) evidence of surveyors down valuing properties with spray foam, In some cases, valuing a property at zero.

I have insulated one room here - Solid brick wall built in 1928/9 - That room is a lot easier to keep warm during the winter, and there is no longer any damp problems in there. Hoping to do a couple more rooms this year including the stairwell (which is going to be <ahem> fun).

femalemonarchfemalecanine

Thank you. I’ll look into internal insulation. I’d been told the loss of space was more like about a foot, but I can live with 7.5cm. 

I like the sound of “no longer any damp problems”😄

Bendy_House

femalemonarchfemalecanine said:

Thank you. I’ll look into internal insulation. I’d been told the loss of space was more like about a foot, but I can live with 7.5cm. 

I like the sound of “no longer any damp problems”😄

I think it could come down to the condition of your current solid walls. If there is no rising or penetrating damp, then - in theory - there's little reason not to simply adhere ~2-3" of insulated-plasterboard on to the insides of the external walls. Jobbie pretty much jobbed, and this will transform the insulation value.

Then check your floors - if these are timber T&G floorboards, then expect them to be pretty draughty. If you don't want to lift them to add a good level of insulation underneath them, at least lift whatever floor covering you have and stick down ~8mm fibreboard underlay sheets (as used with laminate floorings), fully sealed against each other and - especially - around the room perimeter and under the skirtings. That steady percolation of air can really reduce your room temp - I should know.

FreeBear

femalemonarchfemalecanine said: Thank you. I’ll look into internal insulation. I’d been told the loss of space was more like about a foot, but I can live with 7.5cm. 

I like the sound of “no longer any damp problems”😄

If you use a studwork frame filled with fibreglass batts, then you'd lose around 150-200mm of floor space. But I would recommend PUR/PIR foam such as Celotex or Kingspan, and you'd only need 75mm - A better insulator than fibreglass or ploystyrene for the same thickness, but at a slightly higher cost.

One more downside of IWI - If you have radiators under the windows, these will either need moving to another wall or suitable battens fixed to the brickwork to support the weight. Wall mounted kitchen cupboards will also require a similar solution.

BUFF

If they get damp behind any furniture/curtain then there is either a ventilation issue or it's coming through the walls (or a combo of both). Not sure that putting something that isn't breathable  between the heated room interior & the external walls is a good idea if they are damp.?

femalemonarchfemalecanine

I think it’s mainly condensation. I get it on the windows too. I did have a damp expert in and that was his opinion. So making the walls warmer should help?

maisie_cat

We internally insulated our old house, also 1930s detached double skin no cavity. We followed the recommendations on the energy saving trust website and used a wooden structure with insulated panels between the studs and plasterboard face. It made a massive difference although the window reveals were fiddly.

femalemonarchfemalecanine

Thanks Maisie cat I’ll check out that website

BUFF

femalemonarchfemalecanine said:

I think it’s mainly condensation. I get it on the windows too. I did have a damp expert in and that was his opinion. So making the walls warmer should help?

In that case it sounds like a ventilation issue is the root. Have you tried to address that?

femalemonarchfemalecanine

BUFF said:

femalemonarchfemalecanine said:

I think it’s mainly condensation. I get it on the windows too. I did have a damp expert in and that was his opinion. So making the walls warmer should help?

In that case it sounds like a ventilation issue is the root. Have you tried to address that?

I’ve got air bricks and I do have the windows open regularly. I’m not sure what else to do?
I also don’t have cut flowers in water in the house or houseplants, I now have an extractor hood over the hob and keep lids on pans, extractor fans in the bathrooms and utility room.