Extension Cavity Insulation

[osprey]

Just checking: I have an extension being built soon, and I over-rode the architect's initial plan for rendered block-block wall, with 100mm cavity (half filled with insulation boards/batts) and 50mm insulating plasterboard inside. 

 

I requested 150mm cavity with full-fill EPS bonded  beads injected after construction. Reasons being, lack of control of batt insulation, dislike of thick insulation inside, more likely to avoid cold bridges etc. Also because existing house has 50mm bonded bead injected, so familiarity with that product.

 

Am I mad, or is this a reasonable approach? I think I may have some doubting builders.....

[joe90]

17 minutes ago, osprey said:

Am I mad,

No

18 minutes ago, osprey said:

is this a reasonable approach?

Yes

[jayc89]

Makes perfect sense. Don't know why it's not more common. 

[Canski]

It can work out expensive in smaller jobs. What’s wrong with 150 mm full fill cavity bats ?

[joe90]

7 minutes ago, Canski said:

It can work out expensive in smaller jobs. What’s wrong with 150 mm full fill cavity bats ?

I did thst with 200mm cavity 

[ETC]

7 minutes ago, Canski said:

It can work out expensive in smaller jobs. What’s wrong with 150 mm full fill cavity bats ?

Needs good workmanship. Not always achievable.

[osprey]

Thanks for replies.

 

I like idea of being able to see a clear cavity when being built, with no fear of batts slumping, outgassing, not being joined properly etc. What worried me was the unfamiliarity of builders with the idea.

 

And, of course, the familiar 'you need a clear gap'.

[joe90]

54 minutes ago, ETC said:

Needs good workmanship. Not always achievable.

That’s what this forum is about, good workmanship.

54 minutes ago, ETC said:

Not always achievable.

Why not, ?  Mine was with a little attention to detail.

16 minutes ago, osprey said:

the familiar 'you need a clear gap'.

Old news, the batts (that I used ) had a bba certificate for full fill and even when a fault caused damp to get into my batts in one location it didn’t migrate (soak through) .

Edited Saturday at 18:09 by joe90

[Canski]

2 hours ago, ETC said:

Needs good workmanship. Not always achievable.

Hardly rocket science. 

[ETC]

4 hours ago, joe90 said:

That’s what this forum is about, good workmanship.

Why not, ?  Mine was with a little attention to detail.

Old news, the batts (that I used ) had a bba certificate for full fill and even when a fault caused damp to get into my batts in one location it didn’t migrate (soak through) .

I wouldn’t trust a brickie on a priced job to sit the right way on a toilet never mind install cavity wall insulation properly.

Edited Saturday at 22:52 by ETC

[joe90]

2 minutes ago, ETC said:

I would trust a brickie on a priced job to sit the right way on a toilet never mind install cavity wall insulation properly.

I presume you mean “would not” . It’s a shame you tar all trades with the same brush. Despite my many years of being in this trade I would not say the same of architects.  So, who, in your opinion is qualified to instal cavity wall insulation properly?

[Roger440]

5 minutes ago, ETC said:

I would trust a brickie on a priced job to sit the right way on a toilet never mind install cavity wall insulation properly.

 

Indeed.

 

Theres plenty of videos on youtube of builders installing cavity insulation as they build. Lets hope none of them ever build a house for anyone here. And they are putting these videos out to promote themselves.

 

Ive long concluded, most builders simply dont understand insulation.

[Roger440]

Just now, joe90 said:

I presume you mean “would not” . It’s a shame you tar all trades with the same brush. Despite my many years of being in this trade I would not say the same of architects.  So, who, in your opinion is qualified to instal cavity wall insulation properly?

 

Its a good question. And one i cant answer, which is why i do almost everything myself. Unless you are in the trade in some way, finding good ones is largely a lottery. One, which on the few occasions i have had to do it, often have been lacking.

 

Only the plumbers have ever been good.

 

[ETC]

27 minutes ago, ETC said:

I wouldn’t trust a brickie on a priced job to sit the right way on a toilet never mind install cavity wall insulation properly.

Edited.

Edited Saturday at 22:52 by ETC

[ETC]

I haven’t met a tradesman yet that I would trust to do a good job without supervision or knew what they should be doing. Dirty cavities, wall ties sloping out, cavity barriers not installed properly, cut trusses with no support, ICs put in back to front, boiler flues too close to windows, oil tanks too close to buildings or boundaries - I could go on - and these people think they’re experts - Christ!

Edited Saturday at 23:01 by ETC

[ETC]

21 minutes ago, joe90 said:

I presume you mean “would not” . It’s a shame you tar all trades with the same brush. Despite my many years of being in this trade I would not say the same of architects.  So, who, in your opinion is qualified to instal cavity wall insulation properly?

There are Architects and there are those who think they are. I see drawings every single day that most should be thoroughly ashamed of - by both architects and by those who think they are.

[Canski]

1 hour ago, ETC said:

I wouldn’t trust a brickie on a priced job to sit the right way on a toilet never mind install cavity wall insulation properly.

A shocking comment. I can only presume wine or something stronger was involved. 

[joe90]

10 hours ago, ETC said:

There are Architects and there are those who think they are. I see drawings every single day that most should be thoroughly ashamed of - by both architects and by those who think they are.

I agree and the same can be said for brickies but you have not answered my question about who you think is qualified to instal cavity wall insulation.

[ETC]

10 hours ago, Canski said:

A shocking comment. I can only presume wine or something stronger was involved. 

No wine - just years of experience.

[ETC]

1 hour ago, joe90 said:

I agree and the same can be said for brickies but you have not answered my question about who you think is qualified to instal cavity wall insulation.

Brickies with proper training and experience under supervision and with work inspected.

 

As I was told recently “I’m building not buying it” !!

[Roger440]

1 hour ago, joe90 said:

I agree and the same can be said for brickies but you have not answered my question about who you think is qualified to instal cavity wall insulation.

 

The answer surely, ignoring practicalities, is someone who understands what insulation is for and how it works.

 

ie, not leaving gaping gaps, or paths for air to get behind it.

 

Sadly, that probably rules out 95% of brickies. They are, after all, brickies. Their skill is laying bricks.

 

I wouldnt go to my dentist and ask him about my back pain. But they are both in the medical profession.

[joe90]

19 minutes ago, Roger440 said:

someone who understands what insulation is for and how it works.

So the question still stands, who is qualified to instal cavity insulation. In my case I explained what i required to the builder who did as I asked. Others would employ a project manager I guess. I think it’s disingenuous to assume all brickies have no common sense.

[Roger440]

3 hours ago, joe90 said:

So the question still stands, who is qualified to instal cavity insulation. In my case I explained what i required to the builder who did as I asked. Others would employ a project manager I guess. I think it’s disingenuous to assume all brickies have no common sense.

 

Its just another example, of many, where the technology, has fast overtaken the skills and ability of the people who have ended up with it on their plate.

 

Just like cars. The motor trade, by and large, is ill equipped to deal with vehicles as they now are.

 

Im not offering a solution, as i dont see one. It requires people of greater technical ability and understanding to ensure these tasks are done correctly. However, the reality is, such people are unlikely to choose a career of standing in mud and working in the freezing rain, when there are so many other options available to them.

[Iceverge]

A blocklayer is more than capable of installing cavity batts correctly. It's a technically much simpler thing than putting a cavity wall together. 

 

The industry never trained anyone to do it properly, manafacturers make unworkable products (rigid cavity boards), and there's usually zero oversight and reward for a job well done.

 

We still pay per block so effectively want the insulating job done for free. Brickies who make a good job of it loose money becuase they havn't been paid for their time.

 

 

Setting up the incentives so negatively for any human and getting a bad result, it's a bit rich to blame the individual. 

 

 

 

 

[Roger440]

3 minutes ago, Iceverge said:

A blocklayer is more than capable of installing cavity batts correctly. It's a technically much simpler thing than putting a cavity wall together. 

 

The industry never trained anyone to do it properly, manafacturers make unworkable products (rigid cavity boards), and there's usually zero oversight and reward for a job well done.

 

We still pay per block so effectively want the insulating job done for free. Brickies who make a good job of it loose money becuase they havn't been paid for their time.

 

 

Setting up the incentives so negatively for any human and getting a bad result, it's a bit rich to blame the individual. 

 

 

 

 

 

Sorry, thats rubbish.

 

They clearly are not capable for the most part. 

 

Its quite obvious that the concept of a continous layer just isnt understood. Surely thats just bloody common sense?

 

No one trained me to do any of the things i do in my house, but i apply myself, understand it, and i have pride in my work.

 

When i ran my own business, we, almost daily, came up against things we didnt know or understand. So we figured it out. There was no one available to come and hold my hand or tell me what to do.