Do I really, really need a windpost?

[humblenovice]

Hi All,

I know this seems to be a rather evergreen question on here - but I have a dilemma in relation to our house renovation (and the fascinating lives of Structural Engineers).

We are knocking through an internal wall, and have had a qualified SE to come and confirm that there was no beam required to support any load above. However, this SE also then stated that we would need to either leave 550m of a section abutting the exterior wall, or install a windpost, for lateral support. We later had a surveyor round (to measure for windows) who claimed to have considerable experience with structural calculations (but either retired or not an SE), who suggested that this was unnecessary and that the first SE was being over-cautious. We would much prefer to remove the whole of the wall (as architecturally it makes sense for the kitchen layout etc.), but we don't have funds for a whole wind post install.

So now we are looking for a second SE to assess, but I'm a bit concerned that a lot seem to be 'overcautious' with these calculations, and we are going to pay twice for the same ('incomplete'?) advice, and still end up with a mildly flawed finish. So I'd love to hear your opinions please? (I gather @tony1851 seems to be a resident expert here!)

There is a diagram of the ground floor attached to indicate the wall to be removed. All the green walls are cavity walls - the RHS is a 2-storey extension, the LHS is a party wall as we are semi-detached. I'm not sure what other details would be needed, but obviously happy to provide whatever I can!

 

[noseall]

Hi All,

I know this seems to be a rather evergreen question on here - but I have a dilemma in relation to our house renovation (and the fascinating lives of Structural Engineers).

We are knocking through an internal wall, and have had a qualified SE to come and confirm that there was no beam required to support any load above. However, this SE also then stated that we would need to either leave 550m of a section abutting the exterior wall, or install a windpost, for lateral support. We later had a surveyor round (to measure for windows) who claimed to have considerable experience with structural calculations (but either retired or not an SE), who suggested that this was unnecessary and that the first SE was being over-cautious. We would much prefer to remove the whole of the wall (as architecturally it makes sense for the kitchen layout etc.), but we don't have funds for a whole wind post install.

So now we are looking for a second SE to assess, but I'm a bit concerned that a lot seem to be 'overcautious' with these calculations, and we are going to pay twice for the same ('incomplete'?) advice, and still end up with a mildly flawed finish. So I'd love to hear your opinions please? (I gather @tony1851 seems to be a resident expert here!)

There is a diagram of the ground floor attached to indicate the wall to be removed. All the green walls are cavity walls - the RHS is a 2-storey extension, the LHS is a party wall as we are semi-detached. I'm not sure what other details would be needed, but obviously happy to provide whatever I can!

We have a job in the summer whereby the masonry piers (between openings) we will be building, require stability wind posts (Ancon) building in.

 

[stevie888]

Trust a double glazing guy or an SE? Hmmmm.

Nobody on a forum can give you a definitive answer, and at the end of the day the only opinion that matters is BC when they check the proposals

 

[^woody^]

Houses with no corner returns were all the rage for about 1000 years, right up until the mid 1980's when some bloke (probably a shrewd engineer) invented Wind Posts, and the rest is history.

I've yet to see or hear of any of the millions of houses lacking this apparently essential 550mm of brick work, actually fall down. However, I must admit that I have slyly placed my spaniel's basket in the room facing such a non-compliant corner of my old house, and he will hopefully bark his head off at the sound of any cracking during the night.

The only issue I'm aware of with corners with no wall return and a window right into the corner, is that there is no space for the curtains to hang at the side of the window, and it's a bit annoying.

 

[Ivor Windybottom]

The window fitter "surveyor" probably doesn't know or care about the concept and has got away with it, as he normally just replaces existing windows so doesn't get involved with structural issues. Many houses have suffered from issues due to wood windows being replaced by plastic without their "surveyor" appreciating that the stronger wooden window frame was actually supporting the wall, which cracks after. Don't rely on a window fitter's advice.

I've seen lots of old houses with a similar scenario - basically any room that has more than one window on one face has this situation.

I'm sure they never bothered caring in the past. But it sounds like a very sensible precaution to me. If you've ever knocked a wall down then you'll know that the sort of thing you'd be left with could be pushed over pretty easily with little more than a heavy lean. Once you start swinging opening windows and doors off that then it may not collapse into rubble but you could get some ugly cracks.

Mortar isn't a glue, especially not after a decade or so. It's just a filler to let bricks sit together without gaps. The strength of a wall comes from its shape.

 

[Deluks]

If it were my house, I'd err on the side of caution.
We get seasonal movement cracks on one of our walls, whether or not that's related to a previous owner installing a window 3 inches from an external corner can't be proven.

 

[tony1851]

The old wind-post hobby horse wheeled out again by some SEs.

The distance between the party wall and the original side wall of the house seems to be around 5m, which is not excessive for a horizontal span, and IMO no post would be needed, assuming the house is in a sheltered/suburban area and not on the top of Ben Nevis.

As it seems the first floor joists run onto the rear wall(?), they will also provide some lateral restraint to said wall.

 

[noseall]

Houses with no corner returns were all the rage for about 1000 years, right up until the mid 1980's when some bloke (probably a shrewd engineer) invented Wind Posts, and the rest is history.

I've yet to see or hear of any of the millions of houses lacking this apparently essential 550mm of brick work, actually fall down. However, I must admit that I have slyly placed my spaniel's basket in the room facing such a non-compliant corner of my old house, and he will hopefully bark his head off at the sound of any cracking during the night.

The only issue I'm aware of with corners with no wall return and a window right into the corner, is that there is no space for the curtains to hang at the side of the window, and it's a bit annoying.

I'd never heard of a wind-post up till about 15 years ago. Now we fit them with regularity. Our latest job we have been instructed to fit two proprietary Ancon wind-posts into some blockwork.