"Roger Mills" wrote in message
...
In an earlier contribution to this discussion,
wrote:

Does anybody know where I could possible get hold of cavity wall
specs ? basically I'm looking at managing a extension project myself
but I want to be sure that everything is done right and according to
BC. Some of the builders I have had in for a quote tell me that for
the floor be it solid or wooden, they have to dig about 8" down and
then build it up with a mixture of hardcore, insulation and DPM, is
this correct ?

Any advice/help will be greatly appericated.

How are you going about getting Building Regs approval for your extension?
Assuming you're in England or Wales (Scotland may be different) there are
two different approaches which you can adopt. The more usual one is to
draw up (or pay someone else to draw up) detailed plans which contain the
full technical details of how the building will be constructed - and get
them approved *before* getting quotes from tradesmen for the actual work.
These will contain details of the cavity wall construction, floor
construction and insulation, roof construcion, door and window specs,
etc. - and leave little room for argument.

The alternative approach is to do it on a Building Notice - where you
submit much less detailed plans and then negotiate each detail with the
Building Inspector as the work progresses. This gives you more flexibility
to 'refine' the design but also makes it much harder to get fixed price
quotes from tradesmen because the BCO might insist that they do something
they weren't expecting, thus adding to the cost.

It's a good idea - especially if you're doing your own plans - to go to
have a chat with a BCO at your local council and find out exactly what
they'll be looking for before you start. If it's obvious from your
approach that you want to do it right, but are not quite sure what to do,
I have always found them to be very helpful and supportive. They'd rather
help you get it right first time than get into a dispute when they come to
inspect something which *hasn't* been done right.

If you're doing your own project management, this book
http://www.whsmith.co.uk/whs/go.asp?...220&Menu=Books is a
"must read". Looks like WHS are doing a good deal on it, or you'll
probably find a copy in your local library.
--
Cheers,
Roger


Yes it is worth speaking with BCO and if others nearby have had extensions
built recently you may be able to get some good info about the nature of the
ground and likely footing depth issues, routes for foul water and storm
drainage pipes that may affect the groundworks as many people have had
unforeseen expenses once the digging started. However if your architect is
local he may have good knowledge anyway

There are lots of cautionary tales to be told about building work e.g.

My next door neighbour has last month applied for a single storey
garage/store attached to the side of his house as has been told by BCO (not
Planning) that he cannot simply put in a concrete raft for this but must put
in proper footings in case in the future there is an application to add an
upper floor (the difference in cost is 4 extra skips for the waste say £600
and £1200 extra for the concrete and then the extra time and labour which
has doubled the cost of the project)

Tony