Foundation reinstated in one area

[Ossy]

Looks to me like he's looking at the remaining panel of the rear wall to check its capacity to resist wind loads. The removal of this wall, which is currently acting as a shear wall/buttress, won't be providing this once the opening is made. He's therefore adding the post more akin to a windpost than to carry vertical loads. Once the post is installed the knock-on effect is it'll concentrate a point load at foundation level and wouldn't spread far enough to be within reasonably assumed bearing pressures.

I'd concur with your engineer, and it is him providing the PI at the end of the day.

 

[tony1851]

The total width across the back is about 7m unsupported, which is not excessive.
The central panel will take wind load from its own area + 1/2 the openings each side, but the compression from the wall/roof above + the reaction from the beam would be sufficient to counter that without a windpost.

 

[Hornmeister68]

Cheers for all the feedback guys.

I'm just a bit dumbfounded with the amount of documentation I've received when I just want a wall knocking out. I didn't actually realise the wall above it isn't a continuation of the wall I want knocked out in fact my neighbour reckons it's not a load bearing at all. When I mentioned to the surveyor, "I don't fancy ripping up the decking to reinstate the foundations" (at the place he wants the upright), he replied saying he was only saying that as he doesn't know how deep my foundations are (so it's extra support for the upright and load) and then added that he thinks, alternatively, I should dig down at the side of the house then and let him know how deep my foundations are (save ripping the decking up).
It all seems like a lot of graft for one wall getting knocked down.

Anyway I emailed him with some questions the day after his survey, (these were in retrospect of my conversation with him at my home and not the actual survey docs which I hadn't received at that point)......as follows :

"I’ve got three questions for you (which I’ve highlighted in bold lettering).

You mentioned about digging down to see how deep the foundations are, but once the hole has been dug, do you (or anyone else) need to see the depth or can it be filled straight in ? (which I’d prefer as don’t really want a hole outside for too long, for safety reasons with having a 12 year old daughter) and do you need to know the depth of the foundations before you can complete the survey/ drawings ?

Also, I didn’t realise the wall in the kitchen, didn’t go straight up to the first floor (I actually though the wall in my daughter’s bedroom was a continuation of the downstairs kitchen wall) so is the kitchen wall definitely load bearing if it doesn’t continue upstairs ? "

His reply was :

"Thank you for the e mail and appreciate the points raised.

Better to dig the hole and let me know the width of the concrete footing and the concrete thickness which maybe 150 to 300mm in depth and what the ground is like at footing level.

If it is very weak call me and I shall inspect and test. I am in next Thursday and Friday.

Otherwise fill it back in.

The kitchen wall is supporting the bedroom joists which in turn support the brick bathroom partition wall so it is load bearing and my calculations show this for beam sizing.

I do not need to know the foundation information to complete my documents".

All in all, I'm wondering if it's because we live in a clay soil area and have the measurements and workings out revealed something sinister.
When we got the original survey done on the house (when we were buying it) 20 years ago, it said there'd been slight movement in the house but it was arrested.
As I've said, I feel there's a lot of messing around just to get the wall knocked out. Oh, and I haven't got the hole dug yet.

Cheers All

 

[23vc]

All in all, I'm wondering if it's because we live in a clay soil area and have the measurements and workings out revealed something sinister.

That could well be part of it, my sister lives across town in a clay soil area (I’m on sand) and for a very similar extension design, the approach of her SE and building control seem to be massively more overkill than on mine, resulting in more cost and not being able to knock as many walls out.

 

[Hornmeister68]

Ok Thanks, my builder doesn't agree with S/E and says an RSJ is enough but if it meant having trouble in, say, 15 years (for example) with the foundation in that area, (when the builder will be a distant memory) I'd rather get it reinforced now and have an upright in but haven't got a clue if it's overkill.....
……but it brings me back to my original question, how much, approx., is it to get just one area of foundation reinstated ?

Cheers