Expanding foam, sealing tape or both?

AstraMonti

In order to make the doors/windows as air tight as possible would you use both of them? My builder says the foam is enough but I am not convinced and tape doesnt cost that much anyway. If both is the way to go, would you recommend a specific brand of tape?

Thanks

esox28

I'm fairly new to air-tightness, but am at the window stage at the moment and talking to the main airtightness suppliers taping the windows is a must. depending on your wall make up, but in my case i'll be sticking tape to windows frame and tape across the cavity and stick the other side of tape to internal block and then the tape will be covered with expanded metal, scratch 'gray' coat and skim coat.

Joey the lips

Foam will be enough. I use to import it. I know its properties. However if your happy with the price of the tape why not use both as you suggested.

sydthebeat

Standard expanding foam is simply NOT air tight. There is only one air tight expanding foam on the market that i know of and its VERY expensive.

Personally i specify expanding foam to fill gaps and add an extra rigidness to the windows. Then i specify taps to create the air tight barrier.

so both in my opinion is best.

muffler

Edit/ sydthebeat just posted the same

AstraMonti

Thanks for the opinions guys. So once the foam is done and dry, then we apply the tape? Is there any other parts except from windows/doors that we need to be sealed in the same way?

sydthebeat

AstraMonti wrote: »

Thanks for the opinions guys. So once the foam is done and dry, then we apply the tape? Is there any other parts except from windows/doors that we need to be sealed in the same way?

yes, loads.

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,18751,en.pdf

AstraMonti

Thanks and wow that's a big list. I don't think I can do all of them so I am going to go for the most important bits, obviously doors and windows are one thing, what else would you consider as a must-be-done thing?

And also would you recommend a specific brand of tape?

sydthebeat

have a look through all the details and see what they recommend. While its actually not a great set of details, its better than nothing.

the main areas to look at is penetrations through the walls, pipes etc... and also at first floor junction if you have one.... DONT build the joists into the block wall.

It really depends on your house design and the type of junctions and details you have.

At the end of the day theres a minimum airtightness figure you MUST exceed.

sinnerboy

sydthebeat wrote: »

Standard expanding foam is simply NOT air tight. There is only one air tight expanding foam on the market that i know of and its VERY expensive.

Personally i specify expanding foam to fill gaps and add an extra rigidness to the windows. Then i specify taps to create the air tight barrier.

so both in my opinion is best.

Exactly what I would have posted.

sinnerboy

AstraMonti wrote: »

Thanks for the opinions guys. So once the foam is done and dry, then we apply the tape? Is there any other parts except from windows/doors that we need to be sealed in the same way?

According to BSRIA report I read recently ( which I don't have it to hand - sorry ) , as a crude rule of thumb , ventilation losses at external wall openings (windows/doors) typically account for about 25% of air permeability of a house when tested. It constitutes the biggest single element of unintended ventilation losses.

Which makes it a very good staring point - but only that.

AstraMonti

Guys can you suggest someone in Dublin that can do the work for me? I can provide the material if needed.

Edit: Just remembered the Looking for a tradesperson / professional / supplier thread, mods give me a shout if you want me to move it there instead.

muffler

AstraMonti wrote: »

Edit: Just remembered the Looking for a tradesperson / professional / supplier thread, mods give me a shout if you want me to move it there instead.

Do no harm to post there in the usual format. Might generate more replies

cork2

sydthebeat wrote: »

DONT build the joists into the block wall..

So if your not building in the joists what are they bearing on? Just for my own curiosity. Now I'll admit I know very little about air tightness but have done a lot of work on sites in the last two years where air tightness was an a big issue on site. Joists however were built into the block work on all projects and never proved to be a problem nor did doors and windows. On the last project we didn't tape any of the door or window the engineers spec was to foam them with the special foam and that alone sealed them. We found the biggest problem to be trap doors and recessed lights. There's little covers for recessed lights to make a seal in the attic but let's be honest here not all but some trades go into attics remove such things and don't put them back, problem straight away, and as for trap doors I've fitted a lot of them and the doors tend to warp in the length of them from time to time so door rounds and straight away.....seal broken. So all in all ill be building my own house soon and I won't be going to the trouble or expense of air tightness I've lived all my life in houses that weren't air tight and I never had any trouble. That's just my own opinion though.

Poor Uncle Tom

Joist hangers? Not new technology btw.

cork2

Poor Uncle Tom wrote: »

Joist hangers? Not new technology btw.

I'm aware of that but I can't see an engineer specifying a whole house to be joisted with hangers you'd see the odd extension or something but that's about it. In my own opinion it's not best practice I've joisted a lot of houses now at this stage and to be honest hangers are for trimming out opes and you'd bolt on the odd hanger in an awkward spot.

AstraMonti

After a couple of quotes and many not returned calls (it's weird to chase people to give them money!) I ended going with Isocell.ie. They were very eager to meet me and get started very fast as we are in extremely tight schedule. I initially wanted only doors, windows and attic but he told me it would be a big waste of money so I followed his advice and we are airtightening (is that even a word?) loads more. The guys there are using various types of tapes, membranes, glues, foam and all the rest. It's much more expensive than I originally thought, but since we are putting an HRV in it needs to be as airtight as our pockets can sustain. I am hoping to achieve below 2m³ (ideally 1.5) on the test, we will see.

And a question, is the airtightness test being done when you are getting your BER cert?

sinnerboy

AstraMonti wrote: »

And a question, is the airtightness test being done when you are getting your BER cert?

Not necessarily but your BER assessor will want the test cert. So will your "signing off" Architect.

AstraMonti

Is it a legal requirement to do it?

sinnerboy

Emphatically yes.

esox28

have been looking for airtight expanding foam on the net and came across some in US only. Is there some where at home you can order this product or a brand name I can follow up, as window supplier seem only to have there standard foam. can pm please. thanks in advance.

cork2

esox28 wrote: »

have been looking for airtight expanding foam on the net and came across some in US only. Is there some where at home you can order this product or a brand name I can follow up, as window supplier seem only to have there standard foam. can pm please. thanks in advance.

It's definately available in cork anyways bought 6 tubes to today for about 10.00 a tube I'll check the name on the tubes tomorrow and let you know.

sinnerboy

Moderator note

Product names like this by PM only please

iceax

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,18751,en.pdf

very good link , thanks

AstraMonti

sinnerboy wrote: »

Emphatically yes.

Sorry getting back to this. The original planning permission was given back on 2006 (it's a whole estate) so the builders are going with 2006 building regulations. Is a BER/airtight test still a legal requirement?

sinnerboy

If planning permission was granted in 2006 it will have expired in 2011. Best get that issue sorted before all others.

AstraMonti

Thanks, I am not really sure what's the deal. I am not building the house by myself. We bought one from an estate which wasn't finished yet and the builder has let us do our own things (make it airtight, install hrv etc, etc) but the main principal is that he is finishing it for us. As far as I know they are building with 2006 regulations (whatever that means) and that's why I asked above.