Foundations??

[Nickfromwales]

21 hours ago, Iceverge said:

Aerobarrier is a buildhub thing. 

 

 

Typically seems to be used by people to go from "Very good"---> "Excellent" . Anyone who's not aiming for "very good" already is too stupid to understand and should go back to sniffing solvents. 

 

I don't think it's going to cure an absolute leaky bucket of a house but it's certainly the icing on the cake. 

 

It can be redone in an old house but requires Statzi levels of masking to avoid contaminating Aunt Janes prize doilys. 

 

I think it really shines where you've screwed up some element of the design process and want to get the number down. 

 

Properly planned and executed airtightness isn't that hard for the non glue sniffers out there. 

Ahhh...English....such a beautiful language 🤣

[Nickfromwales]

21 hours ago, lizzieuk1 said:

The one issue I could see for us, is that we have been looking at a posi joist roof structure & blown cellulose which, sounds like it may not be suitable for that system. The cutting & fitting of pir between rafters (and now a need to tape all sides) is so painful, not to mention the cost, so we're looking for a better way! 

Simple tbh, you just install the roof, add a membrane internally with counter battens for services, parge the top 200mm or so of woodcrete where it meets the membrane, apply some Passive Purple or primer and then tape the membrane to that. Then AB comes in after you 've done all that, and then Bob's your uncle, Fa..................

[JohnMo]

32 minutes ago, Nickfromwales said:

parge woodcrete where it meets the membrane, apply some Passive Purple or primer and then tape the membrane to that

I used primer on parge coat and airtight mastic/sealant

 

https://passivehousesystems.co.uk/product/gerband-6300-primer/

 

https://passivehousesystems.co.uk/product/gerband-fortax-6400-airtight-sealant/

 

Once set almost impossible to remove, and forms better to the irregular surface.

[Jenki]

On 28/02/2025 at 18:58, Iceverge said:

I assume with EPS ICF it's just a hot knife for services and then plasterboard straight to the EPS? How do you stick the plasterboard? Is it screw to the ICF webs or glue it on? How do you fix to it? Is it a matter of drilling through to the concrete core? 

 

@Jenki @Nickfromwales @FM2015 or any other ICF aficionados. 

 

 

 

Yes please do. Live experiments are always appreciated. 

 

The polysteel Blocks I used have a 30mm steel web every 150mm, so yes got knife to gouge the blocks for conduit. I added. Layer of 25mm PIR so surface mounted 25mm electrical boxes and these were screwed to the steel webs with lightweight steel wafer head screws.

Plasterboard was secured with longer drywall screws for metal studs.

[Iceverge]

3 hours ago, Jenki said:

The polysteel Blocks I used have a 30mm steel web every 150mm, so yes got knife to gouge the blocks for conduit. I added. Layer of 25mm PIR so surface mounted 25mm electrical boxes and these were screwed to the steel webs with lightweight steel wafer head screws.

Plasterboard was secured with longer drywall screws for metal studs.

 

Sounds like a good system. 

 

I'm assuming the walls now feel "solid" to tap with your hand? 

 

How do you fix stuff to the wall? Did you add ply/Osb for the kitchen? How about hanging pictures etc?

 

 

I've not considered it but I suppose insulated plasterboard (as much as I normally hate the stuff) could be a reasonable option for ICF for easily boosting the U value .

[Nickfromwales]

6 hours ago, Jenki said:

The polysteel Blocks I used have a 30mm steel web every 150mm

I like the sound of that. I wish Nudura would release a UK / European metric version of their block, as an 8' block is great for straight walls and getting some area done PDQ!

 

I'll try and bribe them with some Maple syrup and see if they bite.......

[Nickfromwales]

@lizzieuk1 a blown cellulose roof structure would be very quiet in comparison to a SIPs sandwich, especially if it's a shallow or monopitch with anything other than concrete tiles or slates. Rubber membranes over SIPs is my idea of hell. Easy for me to say that but I have been on both types of clients builds and can say that without hesitation.

[lizzieuk1]

11 hours ago, Nickfromwales said:

@lizzieuk1 a blown cellulose roof structure would be very quiet in comparison to a SIPs sandwich, especially if it's a shallow or monopitch with anything other than concrete tiles or slates. Rubber membranes over SIPs is my idea of hell. Easy for me to say that but I have been on both types of clients builds and can say that without hesitation.

Think the blown cellulose is our preference, we don't have shallow pitch and will have blue slates & solar but still like the cellulose option. Only issue may be if we can find a supplier so we can diy it, though not sure how much cost saving to be had compared to supply & install option. 

[Nickfromwales]

I spoke to AB as well. 
 

In their quote there is no penalty per-se for the woodcrete, and defo no premium / surcharge for using ‘any extra product’. 
 

What you get quoted is the price. 
 

Also(!) they do all the prep. So masking doors and windows, sealing ducts, looking for obvious leaks / gaps, and then they ‘do their thing’.

 

Price included time & travel, but they ask that if they’re expected to make a good home great, vs them attempting to seal up a complete bag-o-shite (and not meet expectations), then any majorly obvs stuff gets corrected ahead of their arrival.

 

That doesn’t mean parge the woodcrete btw   

 

They’ve asked if penetrations and 1st fix can be done if possible, or at least penetrations in abeyance, insulation and screed down, but for no boarding or finishes to be present (ideally). They will AT an existing residence but the prep is then huge and probably then chargeable (?).

 

Defo looking to use them for a current SIPs client, if I can get the architect / PD to agree that if AT is meticulous and the test results officially certified / verified conclude, that we then DO NOT have to install the interval VCL.

 

If there’s no infiltration from atmosphere and the exterior of the SIPs is covered by a breather membrane, then moisture or vapour debate should be moot? Anyone care to tell me if that’s not a robust solution?

[lizzieuk1]

14 minutes ago, Nickfromwales said:

I spoke to AB as well. 
 

In their quote there is no penalty per-se for the woodcrete, and defo no premium / surcharge for using ‘any extra product’. 
 

What you get quoted is the price. 
 

Also(!) they do all the prep. So masking doors and windows, sealing ducts, looking for obvious leaks / gaps, and then they ‘do their thing’.

 

Price included time & travel, but they ask that if they’re expected to make a good home great, vs them attempting to seal up a complete bag-o-shite (and not meet expectations), then any majorly obvs stuff gets corrected ahead of their arrival.

 

That doesn’t mean parge the woodcrete btw   

 

They’ve asked if penetrations and 1st fix can be done if possible, or at least penetrations in abeyance, insulation and screed down, but for no boarding or finishes to be present (ideally). They will AT an existing residence but the prep is then huge and probably then chargeable (?).

 

Defo looking to use them for a current SIPs client, if I can get the architect / PD to agree that if AT is meticulous and the test results officially certified / verified conclude, that we then DO NOT have to install the interval VCL.

 

If there’s no infiltration from atmosphere and the exterior of the SIPs is covered by a breather membrane, then moisture or vapour debate should be moot? Anyone care to tell me if that’s not a robust solution?

Crikey that sounds pretty good Nick, so we could build to 1st fix and then get them in without needing to do any parge coating at all?

[Jenki]

17 hours ago, Iceverge said:

 

Sounds like a good system. 

 

I'm assuming the walls now feel "solid" to tap with your hand? 

 

How do you fix stuff to the wall? Did you add ply/Osb for the kitchen? How about hanging pictures etc?

 

 

I've not considered it but I suppose insulated plasterboard (as much as I normally hate the stuff) could be a reasonable option for ICF for easily boosting the U value .

Yes all external walls solid and warm to touch😀.

I don't have any wall cabinets in the kitchen so didn't need to. However the steel strips are every 150mm  so not too difficult TO locate and the fix directly to them.

The TV is fixed to these steel strips, as I used metal back boxes screwed to these strips there is a reference on all walls for a vertical strip, so them just measure across.

 

The polysteel blocks only came in one width (not sure if they are changing with tightening of U values), so it was essential to add external insulation fixed in the same way, with baypole screws and battens, and I added the internal PIR to boosts this and eliminate the hollow wall feel.

For a truly DIY build, I found the process, with meticulous planning, a breeze to carry out, and airtightness is easier to achieve with cheep materials.

 

[Iceverge]

Roughly how much per m2 are the blocks? Did you use them for internal walls too? 

 

The idea of screwing to the metal webs is a great one. Someone in here was faced with drilling and concrete screwing hundreds and hundreds of holes for battens for cladding insulation. Different EPS ICF. 

 

Can't remember who. 

 

As an idea one could use the thinnest EPS ICF as a structural wall. 

 

Then using timber frame cable ties add an external masonry leaf and use EPS blown beads for the cavity. It might be a relatively economical method of getting to very good U values and Airtightness with a durable external finish. 

 

It'd be also excellent for thermal bridging with the ICF. 

 

[Nickfromwales]

2 hours ago, lizzieuk1 said:

Crikey that sounds pretty good Nick, so we could build to 1st fix and then get them in without needing to do any parge coating at all?

Yup. 
I spoke about your build in particular, and they said pick up the phone, have a chat, send some plans and they’ll quote for your consideration.

 

For the price and the expected excellent result I think (particularly for my favourite ICF……woodcrete) it is a no brainer.

 

They said the latest you can get them in, but defo before boarding out, the better. Makes perfect sense tbh.

 

I asked about the validity of me wanting to do a pos/neg AT test after they’ve left, and they’re pretty damn insistent that you would be better off pledging the money to Christ to put towards a new bike. 

[Roger440]

10 hours ago, Nickfromwales said:

I spoke to AB as well. 
 

In their quote there is no penalty per-se for the woodcrete, and defo no premium / surcharge for using ‘any extra product’. 
 

What you get quoted is the price. 
 

Also(!) they do all the prep. So masking doors and windows, sealing ducts, looking for obvious leaks / gaps, and then they ‘do their thing’.

 

Price included time & travel, but they ask that if they’re expected to make a good home great, vs them attempting to seal up a complete bag-o-shite (and not meet expectations), then any majorly obvs stuff gets corrected ahead of their arrival.

 

That doesn’t mean parge the woodcrete btw   

 

They’ve asked if penetrations and 1st fix can be done if possible, or at least penetrations in abeyance, insulation and screed down, but for no boarding or finishes to be present (ideally). They will AT an existing residence but the prep is then huge and probably then chargeable (?).

 

Defo looking to use them for a current SIPs client, if I can get the architect / PD to agree that if AT is meticulous and the test results officially certified / verified conclude, that we then DO NOT have to install the interval VCL.

 

If there’s no infiltration from atmosphere and the exterior of the SIPs is covered by a breather membrane, then moisture or vapour debate should be moot? Anyone care to tell me if that’s not a robust solution?

 

Sounds almost too good to be true!

 

Be sure to keep us updated  if you do get to see this used.

 

As im planing to strip and refurb my house in one hit without living in it (so completely empty), might be perfect for what i need.

[Nickfromwales]

1 hour ago, Roger440 said:

 

Sounds almost too good to be true!

 

Be sure to keep us updated  if you do get to see this used.

 

As im planing to strip and refurb my house in one hit without living in it (so completely empty), might be perfect for what i need.

Yup, I agree it seems a bloody good option, even more so for an EnerPHit level refurb. This stuff goes hunting for the gaps you can't see, you fix the ones you can, B I N G O!

 

If you do go that route I'll head up and join in the foam party lol.

[Roger440]

21 hours ago, Nickfromwales said:

Yup, I agree it seems a bloody good option, even more so for an EnerPHit level refurb. This stuff goes hunting for the gaps you can't see, you fix the ones you can, B I N G O!

 

If you do go that route I'll head up and join in the foam party lol.

 

ill remember that. But dont hold your breath, its likely to be 2027 before i get that far. Outside and barn work first. Got to get ones priorities in order!

[lizzieuk1]

On 03/03/2025 at 23:23, Nickfromwales said:

Yup, I agree it seems a bloody good option, even more so for an EnerPHit level refurb. This stuff goes hunting for the gaps you can't see, you fix the ones you can, B I N G O!

 

If you do go that route I'll head up and join in the foam party lol.

On a slightly different note, any opinions on which is more impactful, u-value or air tightness??

Looking at windows, likely options are upvc 2g mock sash or (possibly) 3g or traditional sliding sash - though struggling to find any with 3g as an option!  Thinking mock will have far better AT than trad sliding. 

[Nickfromwales]

1 minute ago, lizzieuk1 said:

On a slightly different note, any opinions on which is more impactful, u-value or air tightness??

Looking at windows, likely options are upvc 2g mock sash or (possibly) 3g or traditional sliding sash - though struggling to find any with 3g as an option!  Thinking mock will have far better AT than trad sliding. 

Pointless going with a great fabric AT test and then filling the house with poorly sealed, leaky doors and windows.....

 

Cold air infiltration trumps U values all day, every day. 

 

"Far better" will still be "poor" vs a proper AT rated unit, unfortunately. Ask the manufacturers for the statistics of the units you are considering, and compare those to say a Rational entry level AT unit to see how much difference there is.

[Iceverge]

28 minutes ago, lizzieuk1 said:

traditional sliding sash

 

This is a terrible idea. A terrible terrible terrible idea. 

 

Sliding sash windows are on my list of an awful way to build a house. 

 

I'll play with PHPP in the minute to give you some numbers on the importance of Airtightness. 

[lizzieuk1]

26 minutes ago, Iceverge said:

This is a terrible idea. A terrible terrible terrible idea

I had a feeling that would be the response 😆

[Nickfromwales]

27 minutes ago, Iceverge said:

This is a terrible idea. A terrible terrible terrible idea. 

 

Sliding sash windows are on my list of an awful way to build a house. 

Kind of what is was building up to, just I was going to break it to them gently 🤣🤣🤣. 
 

Yea……..sliding sash are horrible. 
 

@lizzieuk1, you can get regular openers that look like sash from outside. These just have the horns added to the opening upper 50% of the window. 
 

[lizzieuk1]

1 hour ago, Nickfromwales said:

Pointless going with a great fabric AT test and then filling the house with poorly sealed, leaky doors and windows.....

 

Cold air infiltration trumps U values all day, every day. 

 

"Far better" will still be "poor" vs a proper AT rated unit, unfortunately. Ask the manufacturers for the statistics of the units you are considering, and compare those to say a Rational entry level AT unit to see how much difference there is.

That was my thought too but, are there any good options for the Georgian proportion windows? 

[Nickfromwales]

Just now, lizzieuk1 said:

That was my thought too but, are there any good options for the Georgian proportion windows? 

That’s going to be for you to find out tbh. That’s one for lots of googling and ringing and emailing of specs.  
 

Maybe someone on here has bought some like this and can provide a link to the supplier? 

[lizzieuk1]

2 minutes ago, Nickfromwales said:

Kind of what is was building up to, just I was going to break it to them gently 🤣🤣🤣. 
 

Yea……..sliding sash are horrible. 
 

@lizzieuk1, you can get regular openers that look like sash from outside. These just have the horns added to the opening upper 50% of the window. 
 

Yes, that's what I was meaning when I mentioned mock sash, there's some much nicer ones too that actually look like sash windows but are on standard casements. But, I can only find 2g ones, hence the question of is 2g(lower u value) with good AT preferable. Just wondering how a 2g compared to 3g will affect our efficiency.

[Nickfromwales]

I think for Georgian style the glazed units just come pre fitted with the bars?