"No Cavity Wall" experience and advice needed

modelreject

Hi,

I am about to purchase a property and am in need of some advice.

The property in question is semi-detached and has no cavity wall or damp proof course.

It doesn't seem to suffer from condensation as it is well ventilated and there are no issues of rising damp that I can see. Obviously I will have a proper survey done but what I am in need of is your experience with such a property (if I did end up purchasing the house)

Are there cavity wall insulation alternatives?
Can you add a Damp Proof Course to a house with solid walls?
How best can I reduce heating costs?

Many thanks in advance.

C

olias

Is it brick or stone? Cavity walls are a fairly recent practice and there is certainly nothing wrong with a solid wall. You can insulate solid walls by drylining with insulated plasterboard, but it would cost a fortune and be very disruptive to have the whole house done, and TBH, the payback from lowering your heating costs won't be worth it. As for a DPC, if there are no problems then 'if it aint broke, then don't fix it!' You can have injected DPCs, but they aren't always 100% effective.

As far as heating bills go, how long is a piece of string? Install double glazing if not already present, fit draft proofing to doors, insulate loft and hot water tank - all the usual things you would do in any house really.

Olias

iamcornholio

Internal insulation on a solid wall is a major job, and you may never recoup the costs. Not forgeting the space you will loose.

External insulation may be an option, but you need to do the sums and think of the altered external appearance.

A better option would be to concentrate on other efficiencies - eg better boiler, loft insualtion etc.

You don't need a damp course if you dont have a problem. Presumably this property is very old, so any probelms with damp would be evident by now, and there is nothing to presume that the situation will be any different in the future

modelreject

I think internal insulation is defintely outof the question. What would be great is if I could get an expert out to do a viewing with me before paying for a full survey. The house has had a new efficien gas boiler fitted and already has PVC windows and doors fitted. My main concern would be the rising damp, if it occurs. Next on the list of importance is the heat loss through none cavity walls.

Does anyone know if there is more likely to be damp related problems in non cavity walls?

Thanks for your advice so far!

dampdaveski

Hi Reject,
a solid wall can be more prone to different types of dampness, such as
1. penetrating damp
2. condensation / mould growth
I suppose there is an increased risk of rising damp as a solid wall is 'likely' to be older than a cavity wall.
However if the property is well maintained, external pointing is good and you can see no signs of visible dampness I shouldn't worry too much.
On a brighter note at least you won't need to worry about changing your wall ties

modelreject

Thanks for that. I will maybe go for a closer inspection with someone who knows the signs. My worst fear would be o buy a property with an incurable, or extremely expensive defect.

knowloads

External insulation is not as hard as some make out, with new brick and stone finishes available on top of polyblock , but internal is a pain as it takes the room sizes down by 2-4 inches all round. Both have advantages, but if it ain;t broke etc etc:
DPC injection is haed to penetrate old stone walls, whats yours made of?

Inroad to include external insulation grants was supposed to be finalised this month, but governments eh.... no rush,
:beer:

iamcornholio

There is some dodgy reporting of the thermal qualitiies of Sempatap.

It's not some magical thermal insulation which will save the planet and save homeowners hundreads of pounds. Rather, its a treatment for mould prevention - ie it is a bit better than having a cold wall - but not much

Check out those thermal images on their site. Somehow, just by lining the walls with Sempatap it has magically made the windows so much more efficient that heat is no longer escaping through the glass! Even the privet hedge in the garden is warmer. Amazing product

iamcornholio

I'm not sure how a company gets onto the EST list, but the Sempatap product is not the magical insualtion panacea which EST and MGC make out.

MGC tout the product as a method for dealing with mould - in which in certain circumstances, it can be sucessful. Their blurb says that it is equivalent to 50mm of caviity insualtion in terms of CO2 saving, and implies (but does not actually say) that it is equivalent to cavity insualtion in terms of thermal efficiency too.

In fact, the thermal insualtion qualities of 10mm of this foam is really very minimal - it is less than some types of wood boards or mdf, and I'd certainly like to see their calculations to demonstate how long it would take to recoupe the cost (about £20 per m2) of using this product

Doozergirl

modelreject wrote: »

Thanks for that. I will maybe go for a closer inspection with someone who knows the signs. My worst fear would be o buy a property with an incurable, or extremely expensive defect.

If you want an old house then the likelyhood is that it simply won't have a cavity. This isn't something unusual. I think virtually every house I've lived in hasn't had a cavity and I've never lived in a house with a damp problem or condensation either (I lie actually, we had a basement flat which had condenstaion and we cured it entirely by re-opening the chimney breast) Damp-proofing treatments can be carried out on a house with no cavity just as easily as one with.

If there is a damp problem then anyone with a slightly sensitive nose would be able to smell it even if you couldn't see it. When you talk about getting an expert out, if you take someone who sells damp proofing then they will, without a doubt, try to sell you a damp proofing product even if there is no problem at all. My house now (no cavities) apparantly needed a new DPC according to the 'specialist' despite the existing one being about 20 odd years old - I have had every inch of wallpaper off and we have been here for nearly two years and there is not even the slightest hint of damp. If you want an impartial view then you will need to pay for that survey - you don't get owt for nowt! 'Damp' meters don't measure damp, they measure electrical current which would be helped by damp, but also by certain materials so they are not an accurate measure.

I wouldn't really draw a direct correlation between a wall with no cavity and a serious damp problem, as you seem to have done. It is totally normal not to have a cavity. We have new Double Glazing, a new boiler, have just had the loft insulated and my house costs £6 a month more to heat than my in-laws who live in a 10 year old house.

modelreject

Thanks for that DoozerGirl. I've been reading a few articles on damp etc and they are clearing things up for me. The main thing now is, if/when I do put an offer in I better get it for a decent price