Air Tightness Membrane and taping

Lemlin

Hi folks,

Could anyone (by pm please) recommend a company who complete air tightness membrane fitting and tapping to windows, doors etc.

I have gotten a quote for nearly 6k from one place for a 3800 square foot house but it seems excessive. Quite is as follows:

1. Supply and fit of air tightness membrane to ground floor and first floor ceilings and second floor.
2. Supply and fit of air tightness membrane wrap to hollowcore slab.
3. Supply and fit of air tightness tapes to all external windows, doors and roof windows.
4. Supply and fit sealant tapes etc. to all service penetrations to external envelope etc.
5. Air Tightness test upon completion of the above.

Its 4800 + VAT. Is that excessive?

gears

Yeah that seems a bit mental ok. PM sent

Lemlin

gears wrote: »

Yeah that seems a bit mental ok. PM sent

Thanks.

voodoo

Gears, can you PM me also if you dont mind? Thanks

dos29

I'd appreciate those details as well Gears, if its not too much trouble.

sinnerboy

regarding air tightness membranes and tapes

AFAIK there are just 3 IAB certified sources

Intello from ECB

Siga from here

Vario from Moy Isover

So anyone seeking installers should start with lists obtained from these 3

homewardbound11

Just had my timberframe done and although it is just a case of running tape through all breaks in the air tightness layer is takes alot of this. The tape, all be it siga, proclima, or moy isover and membranes such as siga, and intello is very,very expensive. Tape at up to 60 euro a roll is not cheap and a roll will not do alot especially in a 3800 sq ft house.
The initial taping i would have put down to a week to a week and a half for the frame only with 2 men doing it. If you add in all the service ducting and electrical cables that penetrate through the openings, and, in my case subbies not informing their subbies of what you mean by DONT BREAK THE AIRTIGHTNESS Layer then you have followup calls that become very difficult to remidy once things progress.
I would suggest that at the price you were quoted that the test be satisfactory to your needs and that the company will remidy any leaks to achieve that values.
Less than 1.5 for mechanical ventillation and less than 3 for natural ventialtion seem to be best practice at the moment. If you get that then they have done a good job.

Let us know wat you settled on for a price. BTW the blower test on a house that size can be 400-500 euro for a day.

Lemlin

sinnerboy wrote: »

regarding air tightness membranes and tapes

AFAIK there are just 3 IAB certified sources

Intello from ECB

Siga from here

Vario from Moy Isover

So anyone seeking installers should start with lists obtained from these 3

Thanks for that. I contacted SIGA and they recommended someone in the Meath area which is near enough me in Cavan. Just waiting on a price now.

Smcgie

Hi folks pm me a rough price also for a bungalow of 120m2.

gears

sinnerboy wrote: »

regarding air tightness membranes and tapes

AFAIK there are just 3 IAB certified sources

Intello from ECB

Siga from here

Vario from Moy Isover

So anyone seeking installers should start with lists obtained from these 3

Thanks for that SB I was just PMing the number for the SIGA (not a contractor) rep that I had dealt with.

Lemlin

2. Supply and fit of air tightness membrane wrap to hollowcore slab.

Is there any need fot this? The crowd which do it have quoted 500 + VAT but two different suppliers have commented to me that it doesn't need to be done.

RKQ

Yes IMO there is a need to supply and fit of air tightness membrane wrap to hollowcore slab. Otherwise the air from the cavity can enter the hollowcore slab & vice versa.

Heat loss at the wall & 1st floor junction can be significant. Have a look at air tightness manufactureres details, Dept of Envirnoment details & Homebond manual.

tred

RKQ wrote: »

Yes IMO there is a need to supply and fit of air tightness membrane wrap to hollowcore slab. Otherwise the air from the cavity can enter the hollowcore slab & vice versa.

Heat loss at the wall & 1st floor junction can be significant. Have a look at air tightness manufactureres details, Dept of Envirnoment details & Homebond manual.

Just to add, that my hollowcore supplier closes in the outer side of cores by 4 inches of concrete to alleviate the need for taping or closing. I believe there are a few more that it comes pre wrapped with a membrane, I saw it recently on another site.

gears

Lemlin wrote: »

2. Supply and fit of air tightness membrane wrap to hollowcore slab.

Is there any need fot this? The crowd which do it have quoted 500 + VAT but two different suppliers have commented to me that it doesn't need to be done.

It does depend on how the slab is installed and on what type of block it is installed on.
If your blockes are, say, 4" on edge and your slab extends into the cavity then you will need to adress the air-tightness. If however your innner leaf is 4" on the flat and your slab only covers approx half the block and the other half will be a 4" on edge which will continue up for the 1st floor wall then your cavity will be intact and there is no need for membranes to wrap the slab. Hope this makes sense.

Lemlin

If I'm going for a 6 inch pre stressed slab (without the hollowcore), is there any need to wrap?

soldsold

Yes,

Wrap the solid slabs too, you will still get air leaks below and between them where they sit on the walls.

cuculainn

soldsold wrote: »

Yes,

Wrap the solid slabs too, you will still get air leaks below and between them where they sit on the walls.

What if you sit the hollow core on a bed of motar and the ends are closed?

soldsold

Gaps between the slabs will leak warm air out into the cavity, mortar will shrink and crack away in places below the slabs. Best bet is to seal it with membrane, its not a very big job to install it however getting it 100% airtight is a different story, my advice would be to install it, cover with mortar and a wide dpc to protect it, and try to have the dpc protect the membrane from the sharp edges of the slabs.

Plaster skim coat is airtight, mortar beds are not.

cuculainn

soldsold wrote: »

Gaps between the slabs will leak warm air out into the cavity, mortar will shrink and crack away in places below the slabs. Best bet is to seal it with membrane, its not a very big job to install it however getting it 100% airtight is a different story, my advice would be to install it, cover with mortar and a wide dpc to protect it, and try to have the dpc protect the membrane from the sharp edges of the slabs.

Plaster skim coat is airtight, mortar beds are not.

Hey Soldsold,

Maybe there is something I am missing, but if the plaster skim coat is airtight whats the purpose of the membrane? (assuming the Hollowcore ends are closed off?

Thanks for your help

RKQ

+1 soldsold.
The skim plaster would need to be very well finished to the underside of the slab to be airtight, so IMO the membrane wrapped over the ends of the slab would provide a better detail - easier to airtight.

To be honest I'd wrap all types of slab / timber joist floors as the overlap of the material onto the wall, above & below the slab is more practical on site.

This junction is a major source of heat loss, do you really want to risk it for the sake of a length of membrane?
Why wait for the thermal image to show air leakage?

Of course its up to the individual and budget but there is some very good advice, from experienced individuals, on this thread.

cuculainn

RKQ wrote: »

+1 soldsold.
The skim plaster would need to be very well finished to the underside of the slab to be airtight, so IMO the membrane wrapped over the ends of the slab would provide a better detail - easier to airtight.

To be honest I'd wrap all types of slab / timber joist floors as the overlap of the material onto the wall, above & below the slab is more practical on site.

This junction is a major source of heat loss, do you really want to risk it for the sake of a length of membrane?
Why wait for the thermal image to show air leakage?

Of course its up to the individual and budget but there is some very good advice, from experienced individuals, on this thread.

True it is only a length of membrane, but I hate doing things for the sake of doing things (if you know what I mean!!)

Say you do wrap the ends of the HC, There is still a gap between the hc and the membrane because it is not adhered to it, so you will still get heat loss there. you will also get heat loss at the angles of the walls where the membrane cannot turn. IMO you would be better off to have the skim coat done correctly and/or tape the joint of the hc and wall

RKQ

cuculainn wrote: »

Say you do wrap the ends of the HC, There is still a gap between the hc and the membrane because it is not adhered to it, so you will still get heat loss there. you will also get heat loss at the angles of the walls where the membrane cannot turn.

No, I disagree 100%.

The membrane is airtight. Good luck with your detail:D

cuculainn

RKQ wrote: »

No, I disagree 100%.

The membrane is airtight. Good luck with your detail:D

Thanks

I'll show you our Thermal imaging when it is done

soldsold

Any heat loss through air leaks between the membrane and the slab is just lost to the upstairs as the membrane is plastered to both the upstairs walls behind the skirting boards and the downstairs walls just below the slabs. Either Nail four inch plasterers expanded metal lath and plaster over or use airtightness mastic to seal the membrane to the plastered walls

igilvarry

Architect spec'd Intello but the builder wants to use Siga. Has anyone got a method on how to compare the two please?

Lemlin

igilvarry wrote: »

Architect spec'd Intello but the builder wants to use Siga. Has anyone got a method on how to compare the two please?

I don't think there's any difference but I'd imagine the builder wants to use Siga because its cheaper. In my local builders providers it is anyway.

galwaytt

soldsold wrote: »

Any heat loss through air leaks between the membrane and the slab is just lost to the upstairs as the membrane is plastered to both the upstairs walls behind the skirting boards and the downstairs walls just below the slabs.

...not quite - before it gets upstairs, as heat lost to the HC slab is also carried out over the walls, and out to the cavity - your HRC is a big heat sink/cold bridge - and is quite happy to absorb all the heat you care to send it's way. Only when the slab has reached equilibrium with everything, temperature wise, will it stop taking heat - from both above and below...

sas

igilvarry wrote: »

Architect spec'd Intello but the builder wants to use Siga. Has anyone got a method on how to compare the two please?

For the hollowcore wrap detail you don't use intello. You use solitex plus i.e. the roofing membrane. The intello isn't robust enough for the hollowcore detail i.e. it needs to resist damage.

Note: Siga is the brand name, not a specific product. Intello and Solitex plus are both made by Proclima.

You need to be careful to use the correct product.

Mods: Apologies if I've broken our product naming rules. I do believe in this case however that the items I've named are on the acceptable list as I believe I've seen them referenced multiple times before.

sinnerboy

sas wrote: »

Mods: Apologies if I've broken our product naming rules. I do believe in this case however that the items I've named are on the acceptable list as I believe I've seen them referenced multiple times before.

No worries SAS there are a limited number of these systems so a little rule bend is ok here

The 3 IAB certed syetems are

Intello
Siga
Vario

homewardbound11

6k was about my costs on the timberframe of 3000 sq foot. They probably spent 2-2.5k on material and the 3 weeks it took 3 men probably accounted for the rest. Siga tape is not cheap although it is coming down. So there is profit in it but there is work also . If you are clued in then do it yourself but if you dont have 3 weeks then forget about it.

Having said that, i'm sayig this alot lately. (if i had the time)

soldsold

Just finishing my own airtightness (bits and pieces that were on the long finger) and I'd agree with the last comment on the time it takes and the material cost.

Airtightness is slow and tedious to get right but this mainly depends on the design of the build. Simple design = simple airtightness job.

Lemlin

homewardbound11 wrote: »

6k was about my costs on the timberframe of 3000 sq foot. They probably spent 2-2.5k on material and the 3 weeks it took 3 men probably accounted for the rest. Siga tape is not cheap although it is coming down. So there is profit in it but there is work also . If you are clued in then do it yourself but if you dont have 3 weeks then forget about it.

Having said that, i'm sayig this alot lately. (if i had the time)

My house is 3300 square foot. I was quoted nearly 6k for taping including the roof areas and two airtightness tests.

However, I'm now getting the roof areas spray foamed for 3k and the service pentrations/windows etc. in house taped with two airtightness tests for 1400. That's 4400 and the spray foam is airtight.

Fella doing the taping told me spray foam is killing his business and he's looking into starting it.

Its saved me 1500 anyway.

galwaytt

Lemlin wrote: »

However, I'm now getting the roof areas spray foamed

....out of curiosity, how do they maintain the 50mm clearance under the felt, required for ventilation, when they use a spray-on system ?

Lemlin

galwaytt wrote: »

....out of curiosity, how do they maintain the 50mm clearance under the felt, required for ventilation, when they use a spray-on system ?

I used breathable felt so I presume that helps.
I've been told I will be given certs for everything and my neighbour does cavity wall insulation and he recommended spray foam fella.
Neighbour is aware of all the regulations etc. (I'm not) but was happy to go with this spray foam.

galwaytt

sinnerboy wrote: »

regarding air tightness membranes and tapes

AFAIK there are just 3 IAB certified sources

Intello from ECB

Siga from here

Vario from Moy Isover

So anyone seeking installers should start with lists obtained from these 3

Just a note (and I've run this by a mod, first......), you are not confined to using IAB certified product....... any product with an EU or CE Certification is suitable, and there are several very reputable ones with other EU, CE or BBA or BRE Certification - and available directly in Ireland as well.

Two that come to mind
ISOCELL (membrane's, sealant, tapes, pipe and protrusion gasket's etc)
Klober (membrane's, sealant)

Both have Irish agents.

Coincidentally, both are Austrian, but I'm quite sure there are other's - a quick scan of IAB/NSAI site today didn't, for instance show up any DuPont products, yet as one of, if not the, biggest membrane manufacturer's in the world, they have book's of stuff. Indeed, we did one project where a specific DuPont product was specified by the Architect.

Just don't be limiting yourselves by NSAI lists (for anything, btw).

sas

galwaytt wrote: »

Just don't be limiting yourselves by NSAI lists (for anything, btw).

Subtle, I'm impressed

galwaytt

sas wrote: »

Subtle, I'm impressed

...I hear ya

...try as I might, I can't seem to find the location of their testing facilities......

...talk to me about SEAI 'approved', say, plumber's, next........ :rolleyes:

B1rds

Lemlin wrote: »

My house is 3300 square foot. I was quoted nearly 6k for taping including the roof areas and two airtightness tests.

However, I'm now getting the roof areas spray foamed for 3k and the service pentrations/windows etc. in house taped with two airtightness tests for 1400. That's 4400 and the spray foam is airtight.

Fella doing the taping told me spray foam is killing his business and he's looking into starting it.

Its saved me 1500 anyway.

Hi just wondering if you could PM who you used for the spray foam and taping as I am going the same route as you. got one quote on the foam so far but nothing for the taping? Thanks

creedp

Hi

Sorry for butting in here but I have a question in relation to airtightness tapes. My builder has just been onto me saying his old school plasterer is very unhappy about having to plaster over airtightness tapes as he is concerned the paster won't stick to the tape and will cause cracking of the plaster along the tape.

I dont think he has a problem with plastering over the the airtight membrane but in some places the builder did not leave sufficient overlap of membrane for it did not protrude out below the plasterboard and ran a strip of tape along the bottom of the membrane to achieve this overlap. I think the pasterer doesn't want to plaster over this tape.

Has anyone any views on this issue? Is he correct to be concerned? Is there any way to get over this issue? Sorry for all the questions but the rep for the airtightness company said the tapes are water based and therefore there was no problem plastering over them.

Thanks

sas

There is a specific type of tape that can be plastered over, it has a fleece surface that plaster will adhere to.

In my opinion, if an incorrect tape was used, the plasterer has a point.

One thought (I'm no expert) is to cover the tape with scrim tape. He may be happier with that.

creedp

sas wrote: »

There is a specific type of tape that can be plastered over, it has a fleece surface that plaster will adhere to.

In my opinion, if an incorrect tape was used, the plasterer has a point.

One thought (I'm no expert) is to cover the tape with scrim tape. He may be happier with that.

Thanks SAS. I'll pass on that suggestion and see how it goes down. I may have been hasty saying that he is not concerned with plastering over the airtight membrane as I understand this is also a problem. Surely the airtight membrane (SIGA) is designed to be plastered over? Isn't this why it is supposed to overlap the ceiling plasterboard so that it can be tied into the plaster on the wall and create an unbroken airtight seal? Is there any reason why a plasterer should be concerned with the membrane? I understand he is requesting that expanding metal/wire mesh be nailed to wall along membrane perimeter to allay his concerns. Is this overkill?

Thanks

soldsold

I had a couple of spots where the airtight tape stuck out a bit and needed to be plastered over, do I just painted on some airtightness primer to leave the tape surface sticky. Both siga and pro clima do these primers and they leave a really sticky surface. I used mesh over the membrane for larger areas for example plastering over the hollowcore membrane wrap, I have never seen or heard of a membrane that can be plastered over except the fleece tape SAS referred to, and I'm fairly sure I've read all the literature from the main airtightness companies - as well as probably everything else ever written about airtightness on the Internet

sas

soldsold wrote: »

. I used mesh over the membrane for larger areas for example plastering over the hollowcore membrane wrap, I have never seen or heard of a membrane that can be plastered over except the fleece tape SAS referred to, and I'm fairly sure I've read all the literature from the main airtightness companies - as well as probably everything else ever written about airtightness on the Internet

Agreed, where membrane needs to be plastered over, you have to cover it with expanded metal first.

The primer is a nice idea. I hadn't thought of that.

Update:
I just read your post fully creedp. The plasterer is bang on the money. That is exactly the detail I will be using. It is the standard detail. You should thank him for that suggestion.

creedp

soldsold wrote: »

I had a couple of spots where the airtight tape stuck out a bit and needed to be plastered over, do I just painted on some airtightness primer to leave the tape surface sticky. Both siga and pro clima do these primers and they leave a really sticky surface. I used mesh over the membrane for larger areas for example plastering over the hollowcore membrane wrap, I have never seen or heard of a membrane that can be plastered over except the fleece tape SAS referred to, and I'm fairly sure I've read all the literature from the main airtightness companies - as well as probably everything else ever written about airtightness on the Internet

Thanks for the info Soldsold. Im really confused now as the SIGA rep who supplied membranes and tapes specifically told me that they are water based and can be plastered over. He told me to ensure the membrane sticks out below the ceiling plasterboard by about 50mm so that it can be tied into the plaster board to create the unbroken airtightness layer. In some places the membrane was cut a bit tight and didn't extend below the plasterboard and he advised that I attach a row of the yellow tape to the end ofthe membrane so that it extends 50mm below the plasterboard and can therefore be plasterered. He specifically advised the this yellow tape is water based and will take plaster!! This is crazy as how is a person supposed to know what to do when the experts are supplying contradictory information. I'll have to go back to the Rep and clarify the situation.

By the way if the membrane doe not extend below the plasterboard and therefore is not tied into plaster doe this mean that the permanaent airtight seal is achieved using the blue adhesive strip I think is called Primur ? I find it hard to understand how this adhesive is a permanent seal as in some places I thought is was peeling away from the block. I wansn't that concerned as I thought it would be sealed properly when tied into plaster.


Thanks