(New) Porch pulling away from house

somedream · 7 Jun 2020

Hello,

So after a nightmare earlier porch build (single brickwork skin, full brick with a square window on one side, joined to the window on the other side - bay window), I had it taken all down and a started anew.

Foundations, (around 450mm or so at least), and brick work is done up. Roof has been put on as well.

Inside has been sand/cement plastered, two layers. However this was all done, around 2-3 weeks ago, and I've noticed the other day, a big gap between the porch and the house wall has started to happen.

I raked out some of the mortar, and can see it looks like the wall starter is coming away from the wall... I'm guessing this isn't normal, but is this fixable without obviously taking down the whole thing? I don't think the foundations are the problem, but I'm not a bricklayer, or know much about the bricks - Is this maybe even normal and needs to be filled with a more flexible joint?

The same thing is happening on the other side, where the wall is less than a 1M high, and no wall starter was used there. Small crack appearing in the plaster inside.

somedream · 7 Jun 2020

johnny2007 · 7 Jun 2020

Oh dear!
Looking at the brickwork I can deduce the quality of the unseen work.
Have they put enough fundations or did they build on grass? (seen it done once)
How did they fix the wall starters?
They're supposed to be bolted to the wall with large 10mm bolts, similar to the ones used on satellite dishes.
It doesn't matter that one of the walls is 1 metre, it still needs wall starters.

somedream · 7 Jun 2020

The foundations were decently deep (I think... anyway, I'm not sure how much they're supposed to be), unfortunately I'm not sure how deep, but they did dig maybe 300-500 and fill in with maybe 200mm concrete. The engineering bricks at the bottom are 2 courses deep into the concrete poured into the middle.

The wall starters were attached using the screws provided https://www.screwfix.com/p/sabrefix-wall-starter-kit-stainless-steel/56037 (5 x Stainless Steel Coach Screws, Washers & Plugs) not sure how big they are.

johnny2007 · 7 Jun 2020

200mm concrete is not enough.
That's why it's collapsing.
You can't rely on wall starters to support a wall, they're there as belt and brace.
All the porches (i mean, mini extension) i built have been cavity double skin, i walked away from landlord insisting on saving a few bob knowing the risk of dampness.
Fundations of 500mm subjected to stable ground (hogging here in most of london) filled to ground level.
Then 2 courses of engineering bricks (or more if house level higher).
So i'm afraid, it's back to the drawing board for you and back to be a tea boy for your builder.

^woody^ · 7 Jun 2020

The problem was that you employed buffoons not builders so the porch had no chance - and that can be seen from just a small part of one image, nevermind looking at anything else.

You need to review your selection process.

Mobo_14 · 7 Jun 2020

Don’t think you’ve had it all taken down either.
One of those is from your post about a month back.

no point coming asking for advice then not listening to it

Get it doon!!!!

dontbelieveawordofit · 7 Jun 2020

this is a prank right

noseall · 8 Jun 2020

johnny2007 said:
200mm concrete is not enough.
That's why it's collapsing.

200mm would probably (width is important) be plenty. Its collapsing because it is likely to be on made up ground.

johnny2007 · 8 Jun 2020

I don't think 200mm would be enough even on solid ground, unless they build a reinforced slab stretching under the porch.

noseall · 8 Jun 2020

johnny2007 said:
I don't think 200mm would be enough even on solid ground

Why? When you consider that there are thousands of houses built on just that thickness and that even todays' over engineered standards, 225mm is the recommended minimum for single storey jobbies.

johnny2007 · 8 Jun 2020

noseall said:
Why? When you consider that there are thousands of houses built on just that thickness and that even todays' over engineered standards, 225mm is the recommended minimum for single storey jobbies.

Because to build on 200mm you need a reinforced slab, not footings.
I attended a garden wall built on 300mm footings and there were cracks opening over an inch after only a year.
I prefer to be safe with fundations and never been a fan of saving on something that it's supposed to be there 100 years +.
Then of course in today's world it's ok to take the money and run and the op's porch is the living example of it.

noseall · 8 Jun 2020

johnny2007 said:
Because to build on 200mm you need a reinforced slab, not footings.

Nonsense.

johnny2007 · 8 Jun 2020

noseall said:
Nonsense.

Would you build your own house on 200mm footings?

noseall · 8 Jun 2020

johnny2007 said:
Would you build your own house on 200mm footings?

Nope. We always mass fill in any case.

Nor would I be shocked to see thousands of houses on them (and less) either. Its not so much about the lack of thickness as the ground beneath and the width v's the thickness of the wall.

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(New) Porch pulling away from house

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^woody^

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