New build house - suspect cavity insulation

[Andehh]

Long story short, i am in the process of routing network/cat5 cables through the house for a home network.

I looked into dropping them down the cavities of the house. From the loft down - drilling through thermalite block - i found a lot of debris within the 'air gap' cavity, and noticed it was all Celotex insulation.

I routed the cables internally instead, then went back to the routing them down the cavity form upstairs bedroom down into lounge below. I had more luck here and dropped the 'fishing line' down several feet without too much issue - took a while though. HOWEVER, when I pulled it up it had a yellow fibre type fluff attached to it which it had obviously been dragged through. Not enough to suspect damage but it definitely wasn't celotex, despite effectively being in the same cavity- only at the bottom.

Now I ask more out of curiosity then anything. House has been standing for 7 years problem free (touch wood) and being a new build, if my house is like this I imagine most new builds are... if corners can be cut they will be cut in the haste of putting the houses up quickly & cheaply etc.

I have a 25 year guarantee from Rockwool and 4 years left of the useless NHBC. The cavity insulation looks similar to the stuff found in the loft.

I will try and post pics this evening.

Can anyone comment? - cheers

 

[freddiemercurystwin]

Is there a specific question in there somewhere? You have a new build, the cavities are not very clear because it was thrown up by a developer.

Or you could just have full fill insulation like this: http://www.knaufinsulation.co.uk/en...f-insulation-fulfulls-zero.aspx#axzz2YdP2ADLk

Really, NHBC warranties exist to comfort mortgage companies against major defects such as subsidence. To ever think otherwise is a bit naïve albeit a common misconception.

 

[Andehh]

Apologies, not so much as a real question - as there isn't much i can do about it - though there is 4 years of [useless] NHBC left if it is serious.

I was just wondering what peoples thoughts were on why it would have Celotex at the top of the cavity, and some form of fibre wool at the bottom. Picture will inevitably show the celotex & yellow fibre and assorted rubble in the air cavity.

I was wondering if anyone had any experience with new builds, and why it would have two different types of insulation in it?

When installed would the insulation be checked before the roof goes on/it gets sealed up or is it just assumed by a building inspector the walls were insulated. if it is just assumed, what stops them just chucking whatever stuff in and shutting it up before anyone finds out? - or is that what they pretty much do?

 

[freddiemercurystwin]

what stops them just chucking whatever stuff in and shutting it up before anyone finds out? - or is that what they pretty much do?

Not much, developer builds are thrown up. Literally. A few inspections by Building Control will be carried out but they won't check every house on a site anyway. If there aren't any problems then its probably not worth worrying about.

As you surmise this is not uncommon and generally problems with damp etc would have probably arisen by now if they were going to.

It would be odd to install both partial fill and full-fill insulation in a cavity assuming its not some unusual build.

It is not right of course but one has to take a bit of a gamble when they by a new-build just as any other house. Many are just poorly built. Try and carry on as if you hadn't looked in the cavities!

 

[Andehh]

An answer I feared and expected! Rest of the house hasn't fallen down, and we can't see any damp issues so fingers crossed.

As I've always said though... Better two types of insulation held in by rubble, then no insulation at all!

 

[rjm2k]

If the cable is just for networking, in this day and age I'd use a mix of powerline adapters and wireless rather than running cat5