insulation & dpc behind window cills

Lynch32

Hi Guys,
would appreciate if you could advise if i am worrying about nothing of if I should speak to my builder


Yesteday the builders decided to start filling in behind some of my window cills. Previous to this i noticed that aeroboard was loosely put behind only some of the window cills (as well as around the windows). I just assumed they didn't get around to finishing it in and eventually that they would. When i came down yesterday evening some of the sment was still wet so i decided to check if infact they added the insulation behind the dpc before they filled it in. I only checked one window and found "no" insulation:eek:.
Also for some of the windows that haven't been filled in - most have no insulation in them and also the dpc could be a little higher in each case. I am just worried now that yesterday they came down and filled in behind the window cills without worrying if 1) insulation was there or not 2)if the dpc was high enough. I heard if the dpc isn't high enough it can lead to dampness later.

Also on my plans it refers to 25 mm kingspan and not that aeroboard stuff. Should he really be using kingspan here (as well as around the windows) or is aeroboard sufficient by todays standards?

Unfortunately when one knows very little about building itself, you worry about everything when u "think" its not been done right. Sometimes a little knowledge can be dangerous.

Thanks in advance
Sharon

sydthebeat

Building by 'direct labour' by any chance Sharon?

There has to be insulation behind the cills, if kingspan is specified then it should be used.

The dpc should be at least as high as the cill, personally i prefer it high enough to be able to be dressed under the window.

Purchanse any HOMEBOND House Building Manual and show it to him....

Its wrong, so tell him to do it again.

Lynch32

sydthebeat wrote: »

Building by 'direct labour' by any chance Sharon?

There has to be insulation behind the cills, if kingspan is specified then it should be used.

The dpc should be at least as high as the cill, personally i prefer it high enough to be able to be dressed under the window.

Purchanse any HOMEBOND House Building Manual and show it to him....

Its wrong, so tell him to do it again.

Thanks a mill sydthebeat, no its a contractor thats doing my house. I most definitely will have a chat with him. Is it easy for him to "undo" the ones he had already done??

So correct me if I am wrong here, once they fill in the sment, i should see a few mm (e.g. 5) of the dpc above it?

Thanks again
sharon

davidoco

Purchase the Homebond book as suggested (good chapter on cement) . Remember a lot of trades have their own way of doing things which may or may not be the way it says so in the book but you're better off insisting on what it says in the book unless they can show you otherwise.

Lynch32

davidoco wrote: »

Purchase the Homebond book as suggested (good chapter on cement) . Remember a lot of trades have their own way of doing things which may or may not be the way it says so in the book but you're better off insisting on what it says in the book unless they can show you otherwise.

thanks, must get a copy alright. Can't believe i spelt cement, "sment":o. Its one of those words i don't type very often
Cheers

sinnerboy

OP get the Homebond manual for your own information . If you have to , torture the lads with it .

And ( don't take this the wrong way now ) turn your weakness into a strength .

What I mean is you are the client . You want it done right , "like it says here in the book" . You don't care how they do it right , or how much hassle it is for them to do only what you are paying them for .

Don't think along the lines of "is that too much hassle for them"

In a funny way the less you ( appear ) to know the better

What you are describing here , and make no mistake , is the builder taking the p***

Lynch32

yeah you are right in what you say. Since I originally posted the message my father has given the contractor a little talking to and he admitted it was done wrong and he will do again. I am going to insist he puts in the 25 mm kingspan in as well, instead of the aeroboard.
I asked my engineer and he said that the aeroboard stuff was almost as good - I have my doubts about this though?
I am just afraid of all the corners that are being cut that we don't notice:eek:

Thanks again
Sharon

sinnerboy

Kingspan is almost twice a good as aerobord . they are not like for like substitutes

Lynch32

sorry would be great if you could advise once again. After work yesterday I trotted down to the site, not expecting anything to have been done with the cills as they were working on the roof.

However they did infact to some sort of a "repair" job on the cills that had been filled in. Basically what they did was - scrape out the a few inches of cement nearest the outside, fired in a extra piece of dpc (which sticks up a good bit a this stage) and fired in some of the cavity wall insulation (cut up to fit) which also sticks up over the cement.

I wasn't talking to the builder yet as not sure if this quick fix is sufficient. My gut feeling is that it "isn't":(, but maybe it is.

My father reckons that there should only be 1 strip of dpc and that adding the second bit is not a good idea - what do you think?

Also not sure about his idea of cutting up bits of the tw50 (80 mm) insulation and jamming it in (as he didn't have any of the aeroboard left).It doesn't have the foil bits on either side. It all seems a little unprofessional, although as u know I am no expert.
Your comments once again would be most welcome

Thanks
Sharon

bauderline

Sharon,

Take the builder aside and explain to him that it is rather obvious he is not doing it correct and that you want it done correctly including the 25mm polyiso insulation and dpc fitted as it should be. Politely explain to him that he will not receive his next stage payment until he complies.

At the end of the day it is not a big amount of work for him to fix this and do it properly it would appear he is being a smart ass. Make it clear to him you know what his game is and you won't let him get away with it.

Regards, Peter.

sinnerboy

Be aware that kingspan type insulations rely on trapping insulant gases .
if it is stripped and mashed like you say - those gases are released .

Get hormonal Sharon - you are entitled to

Lynch32

sinnerboy wrote: »

Be aware that kingspan type insulations rely on trapping insulant gases .
if it is stripped and mashed like you say - those gases are released .

hmm i am annoyed now, thanks for the this piece of info. That confirms it, i am going to insist he takes all out and do it from scratch the proper way this time.

Get hormonal Sharon - you are entitled to

:D, this gave me a laugh. This shouldn't a problem, i feel a hormonal rush coming on as we speak:D

I will let you's know how i get on.

Thanks for all responses
Cheers
Sharon

bauderline

As far as I know that 25mm polyiso costs peanuts, he shouldn't have an issue purchasing a couple of sheets to do the job correctly.

p.

Lynch32

hey bauderline,
sorry for dumb question, but when u mention "25mm polyiso", is the kingspan stuff "polysio". I just know thats a stupid question:o
Cheers
Sharon

newname

get tough with him - you employed him to do a very important job, he is not doing you a favour nor is he your friend. Its a professional relationship.
Your house is too important to be burying your head in the sand and being nicey nicey to avoid confrontation.
Ring him, approach him in person, get your father to speak to him again, but get him to put right his mistakes

Good luck

sinnerboy

Lynch32 wrote: »

hey bauderline,
sorry for dumb question, but when u mention "25mm polyiso", is the kingspan stuff "polysio". I just know thats a stupid question:o
Cheers
Sharon

not a stupid question - you are not a stupid person

polyiso is kinsgpan - ( also available as 1. xtratherm and 2 quinntherm )

bauderline

Sharon,

As sb says its far from a stupid question, the builder consistently refers to the Xtratherm insulation as "polyiso" and has got me saying it now. I am brainwashed !

Its good insulation supplied by the three different vendors mentioned above and I don't think there is much difference in quality nor price. Aeroboard is crap and I can't think of anywhere it would be useful in a modern home given current building regs. One of the engineers on here though might know better !

P.

Lynch32

Thanks guys:)

I am learning as I go along. Only recently figured out what DPC stood for:D
If I were to build another house (no chance of that though), i'd know so much more the second time around. I most likely will be posting more questions in the near future and will be looking for your helpful advise. I am heading off to the site now to sort out my builder

Cheers
Sharon