Does aerobarrier negate need for airtightness detailing?

[SBMS]

Am considering aerobarrier… so far we haven’t done any airtightness detailing for

 

- window junctions/across cavity

- slab floor to wall junctiob

- liquid membrane/parging of internal block work (traditional masonry, 200mm cavity with eco beads)

I have implemented a Tony tray and done airtight board in room in roof with taping..

 

Does aerobarrier negate the above entirely? Or should I do it (was thinking of using soudatight and parging with it as well). 
 

do I need to? I know that aerobarrier gets good results for air blower but does that hold up over time? Eg does it deal with the movement at window joints that tape/liquid membrane does? And if I go around with liquid membrane do I then need to shell out £5k on aerobarrier? I wonder if it’s diminishing returns - the difference in heat loss between a 1.0 blower test result and 2.0 For example is about 150W!
 

 

[JohnMo]

4 hours ago, SBMS said:

Does aerobarrier negate the above entirely?

Would have thought so, but only up to a point, if you have big gaps everywhere, you may be fighting a losing battle. Have you done a pre plasterboard air test? Then you know where you are and can discuss what is is achievable with them.

[SBMS]

17 minutes ago, JohnMo said:

Would have thought so, but only up to a point, if you have big gaps everywhere, you may be fighting a loosing battle. Have you done a pre plasterboard air test? Then you know where you are and can discuss what is is achievable with them.

Not yet but am not sure what it would tell me. I’ve seen case studies that get airtightness from 6 to 1.0 so if I blew 6 today would that mean I should still crack on with aerobarrier? 
 

I worry that aerobarrier gets you a great result on the day but does it persist long term? I know they’ve tested longevity of the material itself but presumably this is fairly controlled. Does it cope with movements around junctions well for example 🤔

[JohnMo]

Hope it's better than decorating caulk, which shrinks after a couple of years and leaves gaps everywhere.

[SBMS]

1 hour ago, JohnMo said:

Hope it's better than decorating caulk, which shrinks after a couple of years and leaves gaps everywhere.

Indeed! Think I might have a go myself with soudatight and see where I get?? Any other aerobarriers out there? What did you do pre aerobarrier

[Mike]

2 hours ago, SBMS said:

Not yet but am not sure what [a pre-plasterboard air test] would tell me. I’ve seen case studies that get airtightness from 6 to 1.0 so if I blew 6 today would that mean I should still crack on with aerobarrier?

It can identify where the main air leaks are so that you can fix them. I'd rather do that than rely on Aerobarrier at that stage.

 

High winds make for a good pre-pre-test (or post-test) too; go around all the junctions slowly & feel for air leaks & mark them or fix them on the spot.

[Nickfromwales]

1 hour ago, Mike said:

It can identify where the main air leaks are so that you can fix them. I'd rather do that than rely on Aerobarrier at that stage.

 

High winds make for a good pre-pre-test (or post-test) too; go around all the junctions slowly & feel for air leaks & mark them or fix them on the spot.

Let’s be realistic? Going around on a windy day with a candle isn’t really going to cut it .

 

I’ve recently been working on what is basically now an EnerPHit refurbishment of a mid 60’s brick and block bungalow.

 

I advised the client to go for a posi joist roof, with an AVCL internally. 
 

At the tops of the masonry walls we parged 300mm or so with standard set tile adhesive, after SBR primer was applied to the new thermalite blocks / original masonry.

 

That was covered in Passive Purple, primarily to act as a quality primer for the AVCL to get taped to.

 

At the junctions between the kicker blocks and the infill screeded sections of floors, we injected 330 foam and then multi-tooled off the excess. This was spot foamed and trimmed again. 
 

Then the screed was primered and the sole plate of each internal stud and 100mm of screed against the plate was PP’d.

 

Then these got taped over with an 80mm tape. This bit was prob overkill seeing as AeroBarrier were in next to “seal the deal”.

 

The brick / block / masonry walls were left untouched, just a bit of foam and some leftover PP applied to the obvious bits. No additional parging necessary.

 

Started off at a respectable 1.2ach, and that was down to 0.5 at 38 mins into the treatment.

 

It got down to 0.2 by about 2 hrs in, and then the chap in charge decided to go batshit crazy and upped the fan pressure to 200pa (from 50); he said “we don’t see these types of projects getting such good results, so let’s get it to a 0.1”. And he did. 👌🤝👍

 

The only piss you off was the laptop didn’t do 2 decimal places, so let’s assume the 0.1ach was something like 0.18, so on the rebound I can say it was definitely a rock solid <0.20ach final test result.

 

Shit hot afaic, for an old masonry hybrid refurb.

 

Around doors and windows, all that was done was the foam, but the windows did get taped afterwards; whether they actually needed this afterwards is anyone’s guess, but for longevity, they got taped a few days after.

 

The roof lights had the splays done in the green propassive AT OSB, and they were taped to the AVCL and then the OSB was taped to the roof lights.

 

This was after Gordon Lewis had been to work his magic, fully filling a rather complex roof structure. He was VERY thorough and even came back the morning after; he was supposed to have been elsewhere, but wanted to go around one more time so he could just work some of the smaller, more awkward voids to his then satisfaction. In a nutshell, he stayed until the job was done and 100% over the finish line.
 

Big thanks and a shout out here to Gordon, so anyone wanting Warmcell blown in please PM me and I’ll zap you his details. FYI he tapes up everything after he’s done, so an AT tested build will still be AT after his attendance.

 

The AB product is more like PVA than caulk, so it’s stretchy and won’t crack or fracture like caulk does. They were adamant that taping the doors and windows was pretty much a waste of time / money.

 

I’ll post some pics in a bit.
 

Places where this got in and sealed up were quite fascinating to see (if you like that kind of thing).

 

[torre]

51 minutes ago, Nickfromwales said:

upped the fan pressure to 200pa (from 50

Obviously there's positive internal pressure when installing the magic gunk, but do they do any final test with negative pressure?

 

Would love to see pics, for larger holes I can see the stuff will gradually build up, but it's not clear to me that the seal would necessarily be as effective when the pressure is reversed.

 

I assume they charge more according to how long and how much they blow, so sensible airtight measures are still worthwhile first

[Mike]

1 hour ago, Nickfromwales said:

Let’s be realistic? Going around on a windy day with a candle isn’t really going to cut it .

it's realistic enough to have spent several hours successfully doing it myself. Even a tiny hole in a high wind feels like someone's blowing cold are down a straw at your hand - no candle required :)

[Nickfromwales]

10 hours ago, torre said:

Obviously there's positive internal pressure when installing the magic gunk, but do they do any final test with negative pressure?

 

Would love to see pics, for larger holes I can see the stuff will gradually build up, but it's not clear to me that the seal would necessarily be as effective when the pressure is reversed.

 

I assume they charge more according to how long and how much they blow, so sensible airtight measures are still worthwhile first

They price per m2 iirc, and I asked the same question. So no matter if you’ve parged the place and use very little product, or you’ve a woodcrete ICF or bare masonry structure, price is the same. 

The larger holes? Well anything that you can see should be dealt with beforehand as best you can, obvs, but to give you some idea of how good this is, bearing in mind this product gets atomised, the results can be seen here. Look for the marble lines in these pics, and the ‘hole’ in the first pic, that was not obvious to the eye, got plugged PDQ!

 

@Mike I’m referring to the ones that your method just won’t find, not the ones it can.   Have a look at these micro fractures in the pointing of the masonry, and where masonry meets blocks. The blocks / bricks themselves are surprisingly airtight as is, and no real evidence of the product having sealed them, but I’m sure it has but it’s just not as easily seen.

 

It got into gaps thinner than a cigarette paper, as you can see right at the bottom of the last pic. Two slight white lines 10mm apart or so, which the eye, candle, or other, wouldn’t have ever detected. 

 

There was a 3.4m long metal lintel which was perforated with hundreds of 6mm holes, and this stuff went into each one and plugged them up nicely.

[Nickfromwales]

[Nickfromwales]

No negative testing as AB only blow. I inspected a lot of the areas where this stuff had done its job, and there’s no obvious threat of it getting loosened by a negative test. It’s in that masonry and any such gap like swimwear!

 

AB test certificate isn’t good enough for you to provide at the end of the build, eg for your “as built” AT score, so you’ll need to do another. The as built test is an average score taken from 10 positive and 10 negative, if memory serves me correctly.
 

I asked the chap there and he said it’s something they’re looking into atm.

 

The bottom line is, I’m seriously impressed by this system and the results it yields in not much time at all.

 

You must fill the obvious gaps up, and do as much as you can to get the best results possible, but this will do quite a good job even if you’ve been lazy I expect.

[Nickfromwales]

First unit was the fan, the second was a 3 stage, digitally controlled diesel heater. It was a very cold day, and it was very reassuring to see that they heated the incoming air to aid the process.

 

Only negative was that every single flat surface, and I mean EVERY one of them, gets a layer of product left on it. This included the screeded floor which was like walking on fly paper for the next 2 days.

 

I was horrified when the team prepped and just laid 2” masking tape onto the flat sections of the new Norrsken doors and windows……with zero dust sheet or other over the glass or vertical sections of the frames.

 

All these guys did was throw poly sheets over the precious stuff and get to work. My only criticism was that this could have been better, and a few things got residual goop on them that I’d have preferred they didn’t.

 

Was this a problem? Nope. It just wipes / washes away pretty easily, so things like pipes and lagging in the plant room will need a bit of cleaning after, which is fine. Just could have been avoided with some better prep.

 

This was the first time I’d been on site during one of these treatments, so next time I’ll do the shitty (more intricate) masking / sheeting ahead of their arrival. 
 

In one of the pics you’ll see a tripod near a window, and that was guffing this stuff out at a rate of knots. I inspected the window after AB stripped their seemingly rudimentary masking off, and I can report that there was absolutely no evidence of them being there. This stuff just doesn’t stick to ANYTHING vertical. Not one bit. Happy days!

 

All told, a great team arrived on site, they were speedy and got straight to business. Prep was done (looks a bit underwhelming but does what it needs to) and they were off to the races in no time at all.

 

Quite an impressive setup with no reliance on electricity etc; as seen they just plonk gennys down and get on with it.

 

I’ll defo be using and promoting AeroBarrier, anytime it’s the obvious choice.

[SteamyTea]

To the best of my knowledge, a water based latex sealant is atomised, then finds it way out via any cracks, slots and holes.

Now pure latex does not have a very long service life, maybe 5 years, but hybrid siliconised latex can last 30+ plus years.

I suspect they use the latter as they are both pretty cheap materials.

[JohnMo]

8 minutes ago, SteamyTea said:

To the best of my knowledge, a water based latex sealant is atomised, then finds it way out via any cracks, slots and holes.

Now pure latex does not have a very long service life, maybe 5 years, but hybrid siliconised latex can last 30+ plus years.

I suspect they use the latter as they are both pretty cheap materials.

So what is the difference between this and various emulsion paints, say a kitchen or bathroom which is more water resistant?

[Nickfromwales]

1 hour ago, SteamyTea said:

To the best of my knowledge, a water based latex sealant is atomised, then finds it way out via any cracks, slots and holes.

Now pure latex does not have a very long service life, maybe 5 years, but hybrid siliconised latex can last 30+ plus years.

I suspect they use the latter as they are both pretty cheap materials.

They say it’s akin to pva. Not sure where that sits in the periodic table?  👀

[Nickfromwales]

1 hour ago, JohnMo said:

So what is the difference between this and various emulsion paints, say a kitchen or bathroom which is more water resistant?

If R&D had said “let’s use emulsion”, or something else, one assumes they’d be using it?

 

This was a concept born in the states and franchised over here, afaik. So it’s been around, successfully, for some time apparently. 

[torre]

1 hour ago, JohnMo said:

what is the difference between this and various emulsion paints

 

Biggest difference I see is the magic elves (well, the big fan anyway) tirelessly directing their sealant into the worst leaks in any hard to reach spaces you've missed and can't easaily get back to. I hope not to need the product but I'll probably have a pre-plasterboard blower test and then assess.

 

9 hours ago, Nickfromwales said:

They price per m2 iirc

 

If I'd known this I might have gone straight to them and saved doing a parge coat!

[SteamyTea]

2 hours ago, JohnMo said:

So what is the difference between this and various emulsion paints

I am not sure, but would think, from engineered properties, that the polymers form longer chains, do not need pigments, UV stabilisers, are more flexible and use water as part of the curing, as opposed to just drying.

When water based paints dry, the water molecules evaporate, leaving just the base matrix.  That matrix, in the case of water resistant coatings, shrinks and replaces the positions that were occupied by water molecules with voids that are smaller than water molecules.  That is what makes them water resistant, water cannot get in.

 

How chemists actually create this is a total mystery as they have about 20 words, which they just rearrange into compound nouns, to make things that are incomprehensible.