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Anyone done internal wall insulation?

(20 Posts)
Falcon1 Thu 21-Sep-17 09:02:53

We have just moved into an old, cold house. The windows are single glazed and draughty so I've been getting quotes for double glazing. But having just spoken to the Energy Savings Trust, I was amazed by how little difference replacing the windows will actually have in terms of reduced heating bills. They reckon it would be about £80-90 a year. Whereas getting solid wall internal insulation would create a saving of about £300!

Has anyone done this? What does it entail and was it worth it?

We'll be insulating the loft (saving of about £240 a year) but wondering if we should do the walls too.

Thank you!

TerribleTrent Thu 21-Sep-17 11:10:42

Watching with interest as we're considering this too.

DrizzleHair Thu 21-Sep-17 11:15:22

Just to manage expectations the money savings you see are unlikely to be this big unless you hear your home pretty hot for a lot of the day - they're calculated based on a standardised heating pattern which few people actually use. As a rule of thumb I'd say an average household should take about 30-40% off the numbers quoted

PigletJohn Thu 21-Sep-17 11:51:26

It's well known that the energy savings from double glazing are tiny compared to its cost, and it can't be justified as a money-saving investment.

But if your windows are rotten or must be replaced for some other reason, it does no harm to have DG.

Double-glazing salesmen prefer to keep their customers in ignorance, as it is a profitable trade.

PigletJohn Thu 21-Sep-17 11:59:11

For payback, loft insulation and draughtstripping have the fastest payback and make a big difference.

Wall insulation makes a big difference because walls are a large proportion of the house (but not in a terraced house).

You only have to dryline the external walls, you can get a bonded plasterboard with rigid foam. You can conveniently do it when redecorating, or hacking the walls about for rewiring. Any existing sockets and switches have to be brought forward to the new surface by a qualified electrician.

You need a skilled plasterer to do a good job. In an older house you need to replicate cornices and picture-rails.

specialsubject Thu 21-Sep-17 18:47:11

We have put up internal drylining on one particular solid wall. The condensation is now only on the windows, much easier to wipe down.

The savings on most things aren't huge but comfort will be increased. Also put up curtain rails ( not the stupid rings and poles this place has) to keep heat in better. Thick curtains with linings too.

OliviaBenson Thu 21-Sep-17 22:11:08

How old is the house? Internal insulation can cause problems as old houses are designed to breathe. Loft insulation and draftstripping windows can make a huge difference.

Mum2jenny Thu 21-Sep-17 22:13:56

I have done internal insulation ie battening internal walls with 2x2s, filling with insulation and then plasterboard and finally skimming with plaster, which seems to work well in reducing heating bills.

geoff409 Thu 21-Sep-17 23:08:45

I agree with OliviaBenson some older houses were designed to "breath", plus depending on when it was built it may be that some of the building materials used now simply weren't available back then, and the way houses were heated was different compared to now too. As for double glazing , we had it done, and as the house was built before the year 2000 and had single glazed windows, we did have condensation problems - but we then had no more draughts, we could keep the curtains open more in the cold weather (used to shut them to help keep the draught out), and also the difference in reducing sound from outside is amazing. My Dad's friend does glazing and said any house pre 2000 built/designed with single glazing will have condensation problems if you change to double glazing- hence the dehumidifier (which is one of the best thing we ever bought).

PigletJohn Thu 21-Sep-17 23:43:57

for internal insulation, it's useful to know that the rigid plastic foam boards have about double the insulation power of the same thickness of mineral wool, so it can take up less room, and needs no battens.

There is also foamed glass insulation slab, which is made in Europe and the US but not generally sold here by builders merchants as there is little demand in the UK, although for large projects they will deliver it by the lorryload from Belgium. It does not burn or rot. I hope availability will improve following the Grenfell disaster.

Falcon1 Fri 22-Sep-17 08:44:23

Thanks for all your replies - you all know your stuff! I confess I'm still baffled over internal wall insulation. I've heard that you lose floor space - is that right? If so, is it much? How much does it cost and is it very disruptive?

Our house was apparently built in 1902. We already have a condensation problem - all the windows in the morning are dripping! One double glazing company said that DG windows would sort it, but then he would say that! Do you think it might actually make it worse?

We had Ventrolla round about the windows and they recommended draught proofing rather than double glazing but I'd also like to keep out noise so not sure if we should just bite the bullet and get double glazing. The windows are sound but have massive gaps around them. At the very least they need restoring so might be just as well to just replace. Not sure yet as we've not had any quotes back yet.

We've also got a 20 year old boiler, wooden floors everywhere and a rotten conservatory so it's basically the least energy efficient house we could have possible bought!

specialsubject Fri 22-Sep-17 09:28:40

Condensation happens unless you don't breathe - first wipe up windows morning of the year today. Go round, wipe up, put cloth outside to dry.

Cacofonix Fri 22-Sep-17 09:34:17

I would be wary about double glazing your 1902 house. Ours is 1900 and has original sash windows and we had them refurbished and draught proofed (which only attracts 5% VAT) and they rattling and draughts have stopped. Our windows were reasonably sound though, not rotten. We have a small condensation problem on the windows for about 2 weeks a year, when the heating isn't on full time and the mornings are cold. We get around this by usually having the windows slightly open at the top and a karcher window vacuum for the few days we need to remove the condensation. We do need to redo loft insulation but the house is not cold at all. Plus we have no issue with cold spots or condensation on walls, which would be my worry if double glazing installed and plugging of all draughts.

geoff409 Fri 22-Sep-17 09:41:34

Hi Falcon personally I think it wouldn't make the condensation worse (only guessing as I can't see your house), but might not make it much better. You are right about the floors and conservatory not helping, but you can only do one thing at a time. Honestly for helping keep the damp a dehumidifier in your worst rooms would help amazingly as a start. Don't get an expensive one, I made that mistake and it packed up, get Argos' own basic version as it's terrific. Window will definitely help with the draft though. Are you able to post any photos?

PigletJohn Fri 22-Sep-17 10:22:06

If your windows are dripping, then there is too much water in your house. Double glazing will make the inner glass surface warmer, but will not reduce the amount of water. So it will condense on the walls or other surfaces.

You can take the water out with increased ventilation, and you can find out where the water is coming from and put a stop to it. Some people have an aversion to ventilation and will not open windows or turn on extractors.

If you drape wet washing around your house, over radiators or on racks, you might as well throw buckets of water at the walls and there is no hope for you.

if you are taking showers and boiling vegetables without turning on a powerful extractor, that's easily remedied.

If you have an un-noticed leak in the plumbing or roof (more rarely, a wall) that may be more work.

If you have damp under the floors or in the cellar, and (unusually) it is not caused by a leaking pipe, then you need to increase the subfloor ventilation (usually by airbricks).

All houses have some humidity from the breathing and perspiration of the occupants. Usually this will be balanced by ventilation, but bedroom windows are particularly prone to misting in the mornings.

Old windows usually have slight draughts, it's OK if they are slight enough to give a little ventilation without losing too much heat, and modern windows should be provided with trickle vents. Sadly they are not compulsory.

Old houses were built with vast amounts of unintentional ventilation, with draughty windows and fireplaces sucking air up the chimneys. It's when you block this in the pursuit of energy efficiency that you need to pay more attention to such things as bathroom and kitchen extractors. But a Victorian house would have been running with condensation in the bathroom and kitchen even when it was new.

Wiifitmama Fri 22-Sep-17 10:37:49

We have just had internal insulation boards added to our bedroom as part of a full redecoration of that room (including flooring). Our bedroom is a massive bay window fronted room in a late 1800 built house (now flat) in London). We have been here 7 years and that room is always 10 degrees colder than the rest of the house due to the huge amount of glass and external wall. We had secondary internal glazing put in which helped with noise (busy road) but did not make much of a difference to temperature. And over the last few years, we have had big mould and condensation issues.

We have only just had the insulation put it (and we also added massive amounts under the floor and in the ceiling) so until we go through winter, I won't know what difference it has made. But we have also put a small dehumidifier in the room recently and have been shocked at how much water it is extracting. We dry laundry in the room overnight and that has no doubt been contributing to the issues over the years but we had no idea.

PigletJohn Fri 22-Sep-17 10:51:53

If you must drape wet washing indoors, try to put it in the bathroom or other small room with an extractor that works, and leave it running. This will suck the water vapour out of your home. Leave the door and window shut to prevent it diffusing through your home.

A typical extractor will run for 50 to 100 hours on 14p worth of electricity.

If you have a cheap, or worn-out extractor that is noisy, you can get a modern one with a ball-bearing motor that will be quiet, and last longer.

Graveyardkate Fri 22-Sep-17 15:38:07

Does damp not gather behind the insulation panels? Surely it’s just preventing the walls breathing from the inside?

PigletJohn Fri 22-Sep-17 16:08:31

During winter, the inside of a house contains warm air, carrying a large amount of moisture. The outside is colder air, carrying less moisture.

When you chill the warm indoor air, it is unable to hold all the moisture, so it condenses out. This happens when the warm, moist air touches a cold window or wall.

The brickwork of external walls will be somewhere between the indoor temperature and the outdoor temperature, so moisture will condense onto the walls and make them damp. There might or might not be so much that you see it in droplets. It might just get absorbed into the plaster and bricks.

The dry-lining insulation forms or includes a barrier that prevents the warm, damp, indoor air reaching the cold brickwork, so it can't add damp to it.

The outside of the wall is exposed to the external air and, when it's not raining, dampness will evaporate out of the bricks into the air. The bricks will form a buffer, absorbing water in rain, and releasing it in dry.

If you ventilate a house in winter, the warm, indoor air, carrying a lot of water, goes out; and cooler outdoor air, carrying less water, comes in. So you reduce the amount of moisture inside the house.

OliviaBenson Sat 23-Sep-17 08:19:49

Double glazing won't solve condensation, it will simply form on your walls instead.

I wouldn't rip out original windows, I would get them draftstripped which makes a huge difference.

You need to tackle the source of water (as per pigletjohn). Ventilation is key.

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