Cavity Wall insulation - damp?

Trixgalway

Hi All,
We have a house built in 2007/8. There is (where we can see a 60 mil aeroboard) and a 40 mil space. Am thinking of getting it pumped this year, cash permitting. Galway based. Have a few questions:

1. Would it be worth it?
2. Anyone recommend a thermal image company (so I could see if we really need it done)
3. Heard some horror stories of houses being pumped but then the dampness comes through the bridge and having to remove block work to scrape out the insulation, please post your stories here (but only based on recently installed insulation for comparisson)

Thanks to all!

BryanF

Trixgalway wrote: »

Hi All,
We have a house built in 2007/8. There is (where we can see a 60 mil aeroboard) and a 40 mil space. Am thinking of getting it pumped this year, cash permitting. Galway based. Have a few questions:

1. Would it be worth it?
2. Anyone recommend a thermal image company (so I could see if we really need it done)
3. Heard some horror stories of houses being pumped but then the dampness comes through the bridge and having to remove block work to scrape out the insulation, please post your stories here (but only based on recently installed insulation for comparisson)

Thanks to all!

is your site exposed?
have you any damp problem at the moment? (damp from external sources not condensation!)
if you don't have damp and your site is not exposed get the cavity pumped. grey bead seems the be the standard and more appropriate than foam. the thermal imaging will show up all your heat loss, not just in your walls, it'll show how crap your windows and generally thermal bridging which is often a more expensive solve (its is a great tool to kick a substandard contractor with though). pumping the cavity is one of the 'low hanging fruit' of energy saving measures

Trixgalway

Hi Brian,
Site is very exposed to wind and rain. No damp at the moment.
Have you heard of any damp corssing the bridge?
-Trix

BryanF

Trixgalway wrote: »

Hi Brian,
Site is very exposed to wind and rain. No damp at the moment.
Have you heard of any damp corssing the bridge?
-Trix

yes but its generally a problem before you pump, so i would be less concerned, as you say you do not currently have damp. best advice i can give is choose your contractor carefully, maybe consider some professional involvement from an arch or arch tech who understands thermal bridging and interstitial condensation and in your case can assess what if any capillary action will occur in an exposed situation with full fill cavity insulation.

Trixgalway

do you have your house done?

BryanF

yes and my families home. and following a survey/assessment i spec this type of work regularly, its one of the cheapest options for improving thermal performance available

Eoghan Barra

We live in an extremely exposed area right on the Atlantic, and pumping with bead (with an additive that makes it all stick together) seems to be standard now on all new builds - they don't bother putting any insulation into the cavity during wall construction at all.

I doubt if this method would have become so universal if there were a risk of water ingress (?).

MicktheMan

Trixgalway wrote: »

Hi All,
We have a house built in 2007/8. There is (where we can see a 60 mil aeroboard) and a 40 mil space. Am thinking of getting it pumped this year, cash permitting. Galway based. Have a few questions:

1. Would it be worth it?
2. Anyone recommend a thermal image company (so I could see if we really need it done)
3. Heard some horror stories of houses being pumped but then the dampness comes through the bridge and having to remove block work to scrape out the insulation, please post your stories here (but only based on recently installed insulation for comparisson)

Thanks to all!

Just to add to what others have said.
1. Pumping wont dis-improve the thermal retention properties but may not add a lot either depending on what the main heat loss mechanism is currently. Your house is exposed so airtightness may well be an issue. What type of house is it (bungalow, 2 storey, dormer etc)? Are draufgts a problem?
2. May be able to recommend if needed.
3. I have not yet come accross a case of where pumping the cavity was the sole cause of internal damp.

suitseir

Following onto this thread.......my neighbour got his walls pumped (south facing 3-bed bungalow) with the beads.

A year on and the only complaint he has was during the summer months....he found the inside of his house on the cool side?

Any ideas?

Moanin

suitseir wrote: »

Following onto this thread.......my neighbour got his walls pumped (south facing 3-bed bungalow) with the beads.

A year on and the only complaint he has was during the summer months....he found the inside of his house on the cool side?

Any ideas?

I would imagine that means the insulation is doing its job correctly????

1865

Can anyone tell me how efficient the bead insulation is. i have an old house with no insulation at all - just stud and plasterboard. I am preparing to rip the lot out and replace it with the foam backed plasterboard.
I would be delighted to find a cheaper and quicker method of insulating the house but it needs to be well insluated.

tusmaith

1865 wrote: »

Can anyone tell me how efficient the bead insulation is. i have an old house with no insulation at all - just stud and plasterboard. I am preparing to rip the lot out and replace it with the foam backed plasterboard.
I would be delighted to find a cheaper and quicker method of insulating the house but it needs to be well insluated.

hi, when you say - you have an old house with no insulation at all - just stud and plasterboard" are you referring to how the external wall is insulated?
how is the wall constructed - hollow block or cavity wall or solid wall.
The bonded bead insulation is only suitable for pumping a cavity wall where there is a cavity to be pumped.
when you say that you are "preparing to rip the lot out and replace it with the foam backed plasterboard" this sounds like drylining. There are grants available under the Better Energy Home Scheme for this www.seai.ie

tusmaith

MicktheMan wrote: »

Just to add to what others have said.
1. Pumping wont dis-improve the thermal retention properties but may not add a lot either depending on what the main heat loss mechanism is currently. Your house is exposed so airtightness may well be an issue. What type of house is it (bungalow, 2 storey, dormer etc)? Are draufgts a problem?
2. May be able to recommend if needed.
3. I have not yet come accross a case of where pumping the cavity was the sole cause of internal damp.

Hi,
NSAI published guidance in 2009 relating to conditions in which the partial filling of cavity walls are acceptable.
i cannot find this on the NSAI website, from memory it stated that a minimum cavity width of 50mm had to be in existance where there was existing insulation present. a minimum cavity width of 40mm was ok if there was a "masonry to masonry" cavity.
has anyone else come accross this?
applying this logic, It would not be advisable to pump the Original Poster's house???

1865

Thanks Tusmaith.

The house is a Victorian (hence the 1865 name) building with a 1930 ish extension and is solid wall / redbrick with the 1930s bit in a sort of mass concrete/ rubble and concrete mix about 25 cm thick.

There are no cavities at all and the interior has stud work with plasterboard nailed to it. It isn't suitable for external insulation due to the eves and red brick front. So I am looking at internal insulation options.

I wondered about the grant but hope to do most of the work myself so I assumed that I wouldn't be able to claim it.

Any opinions would be appreciated.

BryanF

1865 wrote: »

Thanks Tusmaith.

The house is a Victorian (hence the 1865 name) building with a 1930 ish extension and is solid wall / redbrick with the 1930s bit in a sort of mass concrete/ rubble and concrete mix about 25 cm thick.

There are no cavities at all and the interior has stud work with plasterboard nailed to it. It isn't suitable for external insulation due to the eves and red brick front. So I am looking at internal insulation options.

I wondered about the grant but hope to do most of the work myself so I assumed that I wouldn't be able to claim it.

Any opinions would be appreciated.

use breathable natural insulations (hemp or wood fibre would be my preference but mineral wool will do) - its really important that you install a taped & sealed vapour barrier on warm side of the insulation behind plasterboard.

tusmaith

BryanF wrote: »

use breathable natural insulations (hemp or wood fibre would be my preference but mineral wool will do) - its really important that you install a taped & sealed vapour barrier on warm side of the insulation behind plasterboard.

Hi 1865,
Please see below for some further reading about the subject in hand…..
Internal wall insulation may not be suitable where rain penetration occurs or where damp
proof courses may not exist in older buildings. For guidance on insulating traditional buildings
(dwellings constructed pre 1940) refer to Changeworks. Energy Heritage – A Guide to
Improving Energy Efficiency in Traditional and Historic Homes. Edinburgh: Changeworks
(2008).
http://www.changeworks.org.uk/uploads/83096-EnergyHeritage_online1.pdf page 44 on.....
http://www.ahg.gov.ie/en/Publications/HeritagePublications/BuiltHeritagePolicyPublications/Energy Efficiency in Traditional Buildings (2010).pdf
I would agree with BryanF about the installation of a vapour barrier. You might want to reconsider installing an insulated board.
I would advise that if you are unsure – talk to a suitably qualified professional in relation to this.
I would not rush into doing this job, consider the health benefits for both the occupants and the property.
Interesting job by the way!

COASTAL

Hi guys
Here is my eperience with beaded insulation.
I am living very near the coast and just have completed building a domestic garage. 4" block, 4" cavity, 4" block.
I decided not to put in any insulation while I was building and I pumped the walls with beads instead.
The insulation was pumped in last october and the inside walls were plastered at the same time.
The outside has two coats of sand plaster both of which had waterproofing plas used in the mix.
Every time that I get heavy rain with south west wind ( which is at least twice a week ) the inside of the south facing gable and west facing wall comes to life with dampness and you can see the outline of every block.
I have since found different bits of information on the internet which suggests that FULL FILL beaded insulation should be avoided at all costs in coastal or exposed areas.
The installers and manufacturers of the beads both deny that there product is allowing water through but you do not have to be a scientist to understand that the outer block is porous so heavy rain will penetrate it but if the cavity was empty then the water could go further so the insulation has to be allowing it to make its way to the inside leaf.
The north and east facing walls are bone dry inside but heavy rain is very rare from this side.
I have been pulling my hair out over this for the last couple of months and I have just spent over €400 euros on 6 gallons of a product called " watertite " which hopefully will solve the problem by sealing the plaster from the outside. I am waiting for the weather to improve before I can paint it on but I will post the results here over the next month or so.
Retro fitting these beads seems to be ok because if water gets through then it is normally stopped by the existing insulation which acts a dampcourse but I would not reccomend pumping the whole cavity with it..

Merch

BryanF wrote: »

use breathable natural insulations (hemp or wood fibre would be my preference but mineral wool will do) - its really important that you install a taped & sealed vapour barrier on warm side of the insulation behind plasterboard.

would a breathable membrane be needed on the cold side, so any moisture cant get to the insulation but can escape?