I have an extension that was built outside the original back door and
window (please see picture http://63.218.54.74/knockwall.jpg). The wall
was originally the exterior wall of a 2-story 4 bedroom house. I want
to knock out the middle section and under the window.
The wall is about 260mm (10") thick and seems to be two blocks wide
with a gap in between. The total distance across the door and window is
3m.

I was thinking of supporting the wall with a series of wall supports
(e.g. hired from HSS) while I fit a beam over the old window and door.

Do I really need to hire a structural engineer for this ? Note that I
won't be doing the work myself, most likely hiring a builder of some
sort.

Is there any rule of thumb for calculating the weight of the structure
above? The wall supports from HSS are only rated to 340kg which is
pretty miserable compared to the "super prop" which supports 12ton.

Any advice appreciated,
Chris.

On 1 Jun 2005 11:38:38 -0700, "Chris"
wrote:

I have an extension that was built outside the original back door and
window (please see picture http://63.218.54.74/knockwall.jpg). The wall
was originally the exterior wall of a 2-story 4 bedroom house. I want
to knock out the middle section and under the window.
The wall is about 260mm (10") thick and seems to be two blocks wide
with a gap in between. The total distance across the door and window is
3m.

I was thinking of supporting the wall with a series of wall supports
(e.g. hired from HSS) while I fit a beam over the old window and door.

Do I really need to hire a structural engineer for this ? Note that I
won't be doing the work myself, most likely hiring a builder of some
sort.

Is there any rule of thumb for calculating the weight of the structure
above? The wall supports from HSS are only rated to 340kg which is
pretty miserable compared to the "super prop" which supports 12ton.

Any advice appreciated,
Chris.

Assuming this q is not a wind up .......

BCO will insist on an engineers design. My mate did something similar,
and he had the BCO round 5 times to check this bit of the work.

If you don't hold the house up with enough supports, it will come
down. Its not just the weight of the bricks, its the floors,
furniture, roof, wind load (if you get a storm half way through the
job).

When the beam (that has to be the right size) goes in, you have to be
sure your walls can take the load, and the foundations below those can
take the load.

If you don't have a building regs cert, you will loose piles of cash
when you come to sell.

If you screw this up, and your house is in a terrace, you may have to
pay for fixing half of the terrace when that comes down too.

Rick

Didn't mean to give the impression that I was going to do this work
myself, just wanted to understand what is involved so I could sound
knowledgable when speaking to the builder :-)

Got a builder to take a look and he said he'd use Acro props for
temporary support and put in an RSJ. Quoted EUR 2k ( GBP 1,355)
including the RSJ.

He said he is insured, I guess I'd better ask for a copy of his
insurance cert before giving him the green light !

I'm in Ireland, not sure what the story is with the building reg, might
be a good time to find out.

Thanks,
Chris.

Chris

We are trying to have something very similar done shortly - even down to the
dimensions of the wall and the span of the RSJ.

We have had an Engineers report done (£180) and he pointed out that the
piers at either end will almost certainly need underpinning. The original
quotes for the work were about £1500 plus the engineer estimated about £700
for teh underpinning.

Tim

"Chris" wrote in message
oups.com...
Didn't mean to give the impression that I was going to do this work
myself, just wanted to understand what is involved so I could sound
knowledgable when speaking to the builder :-)

Got a builder to take a look and he said he'd use Acro props for
temporary support and put in an RSJ. Quoted EUR 2k ( GBP 1,355)
including the RSJ.

He said he is insured, I guess I'd better ask for a copy of his
insurance cert before giving him the green light !

I'm in Ireland, not sure what the story is with the building reg, might
be a good time to find out.

Thanks,
Chris.