Healthier option than Insulated drylining with Kingspan K17/TW56?

ReadySteadyGo

I have been reading about the condensation and mould risk when you internally dryling a house with the typical Kingspan/Xtratherm board. (i.e. warm moisture laden air getting behind the board, condensing on the cold wall, and mould growing)

I am renovating a 3 bed semi, and want to get the walls down to building regs u values. What products could you recommend to do that? Or what would you do to lower the risk of condensation?

My house is cavity block, suspended timber floor and I have it back to the bare block

Thanks,

Sean.

sinnerboy

ReadySteadyGo wrote: »

what would you do to lower the risk of condensation?

Answer don't try to

ReadySteadyGo wrote: »

get the walls down to building regs u values.

by dry lining - only by external wall insulation.

ReadySteadyGo

EWI will not fit in the budget, and will not suit the house. In an estate, very narrow side entrance, semi d, brick finish on bottom half of front of house.

Why do SEAI recommend and grant aid internal drylining?

Is there no building science answer to the problem? e.g. a highly breathable material, which can absorb and buffer mositure peaks?. I think I read somewhere that that was an option. But I don't know a product name etc.,

imitation

I wonder if the condensation risks of dry lining are overstated a bit. On one hand most threads on forums about the topic have a post or two of bad experiences, on the other many people I know who have done new builds have used it with no issues (So far...).

I wonder is this due to drylining being used in older homes with existing moisture problems or some other typical scenario.

wirehairmax

I dryline a lot of old houses and buildings and most of them dont have any existing ventilation. By simply drilling a ventilation opening large enough to provide an air change rate proportionate to the size of the room, condensation and unhealthy air should be dealt with. However ventilation needs to be controlled. No point in having all your heat pouring out through a hole in the wall. Use a vent cover you can control. Also by simply leaving a window open for half an hour a day, at least you are allowing fresh air to circulate. All this talk of condensation and mould is overblown in my opinion. If EWI were more economically viable it could be an alternative to internal dry-lining. Also the correct use of a vapour barrier is very important.

ReadySteadyGo

How are you implementing you dry lining? Composite boards? or a custom build up?

I too wonder about that. I guess part of the problem is that their are so many ways to build a house, when you dryline the internal wall you can get different results. As the SEAI grant is aimed at retrofitting existing houses, and the houses most likely to take it up are the ones with no insulation, I think cavity block built houses would be a typical use case.

The problem as I see it, is that the more insulation you put, the colder the cavity block wall will be, which increases the risk of condensation, and hence mould. People have not been putting 8cms of insulated composite board on the inside of cavity block houses for long enough to know what the consquences are likely to be? And you may only find out the consequences if you test air quality or take the board back off, which is likely not happening to any great extent yet.

sinnerboy

ReadySteadyGo wrote: »

People have not been putting 8cms of insulated composite board on the inside of cavity block houses for long enough to know what the consquences are likely to be? And you may only find out the consequences if you test air quality or take the board back off, which is likely not happening to any great extent yet.

+1

ReadySteadyGo

Doing more research - What about

Softboard
Foam Spray
woodfibre board
calcium silicate boards

Anyone know what depths of these you would need to get the building regs .27u
(and hence hopefully claim the SEAI grant)