Cavity Wall Insulation Question

societys_child

Ray_Lloyd wrote: »

Hi Harryhound the vent is an existing one but the insulators joined the outer and inner with a pipe and yes we do have a gas back boiler and gas fire, as the air flow from out side is now very direct, e.g. can't disipate up the cavity it comes through at gale force so what i was thinking about was to stuff the vent pipe with open pore foam which would allow air through but not at wind strength.

regards Ray

Could you perhaps fit some sort of baffle outside. A plate, larger than the air brick, spaced away from the wall that would still allow air flow.

Edit: you can buy them to fit over the air brick and allow air to flow in from the bottom - might stop the gales blowing through.

angel00079

We are going to board out the loft in our 70's house. Balls about the size of a bin liner have appeared, probabably happened over a few years. These are white and bits disintegrate on touch. A few years ago these were raised areas that were hard. The location of these balls would suggest that they are part of the cavity wall insulation.

I have looked at the house paperwork which shows a guarantee for Urea Formaldehyde Foam Insulation AKA UFFI which was carried out between 1977 and 1979.

From reading I have found that UFFI is banned in Canada and harmful when tested on animals in high doses. Information would suggest that levels in wall insulation would not be this high but I want to make sure that it is disposed of safely and correctly. I would value advice on this.

There is also the high possibly that the insulation is no longer working. Would the old insulation need to be removed?

jcwilson

I have cavity wall insulation and now have some efflorescence on one part of the wall. Installer has inspected and tried to tell me it was possibly salt off the road - the look on my face stopped him in his tracks. He is coming back with another inspector - is there anything I should know to help get this resolved. House has been fine for 50+ years until cavity was filled. How should I deal with the supplier.
Many thanks in advance!

FLINT

JCwilson,

Hi there I think I am in a similar situation to yourself. I have posted recentely that I have just had my Cavity wall insulation removed on the advice of the installer.

I too have salt efforfessance on internal walls, I am waiting on a visit from the companies surveyor tomorrow (Tuesday 23/08) to take a look at damages I am claiming against them for.

I will post what he says and how my claim is progressing.

Yummy-Mum

Help! I'm really keen to get Cavity Wall Insulation installed in my house to try and reduce heating bills. my frined is having the coated beads installed by an approved installer, but the chap I've had round to my house said they aren't any good and can cause damp, so he suggested mineral wool. My house is only 16 years old and has no problems, so I'm just keen to be a bit smarter with energy saving, but this chap has now confused me.

Do I go with the wool or the beads - which is best?

teneighty

A 16 year old house should already have a reasonable level of insulation to the external walls.

Be very careful about adding additional insulation and I certainly wouldn't consider using a firm that didn't realise such a new house shouldn't need extra cavity wall insulation.

ARJONES

I am looking into problems that have occurred with cavity wall insulation for my third year project, if you have had any problems due to cavity wall insulation in your home would you please be able to email me regarding the problems to JonesAR8@cardiff.ac.uk
I would be ever so grateful
Thanks

fabsternation

Oh dear having read this thread I am now confused as to what to do.

I've just had a surveyor/salesman visit and he has said we can have 50mm cavity wall insulation done to our 1950s Detached house for free under the government's grant scheme.

We are in an exposed plot and when it rains, often it beats against the house and the sides get soaked.

My original intention was to get cavity & loft insulation free under the govt's scheme, as I need to do this to get the energy efficiency rating bettered to a D or higher so we can install our solar panels at the better 16p tariff since we only have Economy7 and are not connected to the gas mains.

What sort of cavity insulation should I be looking for considering the house side walls get wet when it rains as the wind beats against it? I am hearing horror stories of damp issues and currently the house is draughty but no damp. I was also advised the compulsory need for an air vent as we have a real fire, which they say is £40. What is your view on this please? Compulsory? £40?

Apparently, we cannot get the loft insulated by the contractor as the head-height up there is less than 1.5m and the contractor said their installers won't do it due to H&S(?) It sounds like I am better off buying some and rolling it down myself!

What is your view with these Free insulation schemes? Anyone had encouraging experiences? I'm in two minds as to cancel as I am worried about the damp issue, given this house is damp free, despite being so exposed to the elements.

I really appreciate any advice, thank you

bye_bye_band_G

Fabsternation, we've had cavity wall insulation installed today by the free government scheme.
Until I read this thread I'd never even considered there could be problems with damp etc, and I was reading this as they were pumping the stuff in! I asked them if damp is often a problem post-installation and they said only if it's installed incorrectly, which I guess doesn't help you or me much!
I can try to be a bit more helpful about the air brick tho, as I've had to have it done. The rule is if you have a gas fire, if it's more than 7.2kw you must have the air brick, I assume it's the same for a real fire. I didn't want it and thought about refusing to let them put it in after they'd done the walls, I thought what are they gonna do to me if I say no? Well the answer is their head office would be informed and then someone gas qualified would come round and label our gas fire as unsafe and cut off the gas!! I let them do it.
There was no mention of a charge for it. It was flippin cold and draughty round that area after they'd put it in so it's got a cushion stuffed up against it for now, waiting for a better idea for concealment that can be easily removed if we have the fire on.

Plain_Speaking

There are ventilation requirements for boilers/heating appliances, as mentioned above, but also timber sub-floors require adequate ventilation through air bricks to prevent rot to timber ground floors.
Some cavity wall insulation firms ignore air bricks and insert insulation into the wall cavity which effectively blocks air bricks up.

For traditional uninsulated cavity wall properties, (built approx 1930s to 1980s), with suspended timber ground floors, (ie not "solid" ground floors), they receive ventilation through the external wall air bricks to a ground floor void.
It is important to sleeve around air bricks prior to cavity wall insulation to prevent blocking the air flow to the timber sub-floor. Blocking the air vents can lead to dampness in ground floor timbers. In a worse case, it could lead to dry rot in the timber floor.

If the property is in a very exposed location, (eg coastal or top of a hill or parts of Scotland), it is generally best to avoid cavity insulation and preserve the cavity.
For buildings in normal exposure and no history of dampness, cavity wall insulation can be benificial if installed correctly.
A pumped beaded insulation fill is the best to avoid damp being transmitted accross a cavity. Beads are resistant to water penetration.
Next best is the blown fibre fill. If kept dry this is an effective insulation material. If saturated the effectiveness of the insulation is significantly reduced.
Historically foam fills have been associated with damp problems and should be used only with caution in protected situations.

Make sure you always use a competent installer.