sunsidence or nothing to worry about ??

[puzzlebobble]

Hi,
I'd be really grateful if I could get the advice of any of you guys/gals out there.

i've owned a victorian house for two and a half years. It'd had a paint job not long before i moved in. This crack appeared a while after I moved in. It might have got very slightly bigger over this time. the crack is at most 1mm.

i thought i'd have a look in the basement and saw this below:

apologies i forgot to rotate them before loading. Left is top. There are some cracks below the crack upstairs. You can just about trace a path bottom to top. some of the cracks are approx 7mm but some of that i think is where mortar is missing. in the wide cracks there's well over a cm of dust/dirt. It looks to me to be roughly on the border between house and bay window. There are only bay windows on the ground floor.

There are no other cracks anywhere in the basement. There are no cracks on the exterior of the house. There is no crack between the top of the bay window and ceiling or in the room above.

Do you think this is anything of concern? What should i do about it?

also; I'm guessing that the thin layer or bricks with holes in it is to with stopping damp? the level of these bricks is lower than the garden out side by 1.5 bricks. If my two neighbours (terrace) have these bricks at the same level then they both have the same. Do i need to lower the ground outside?

many thanks for and advice you have!!!

 

[Joe Malone]

At this stage the cracks are nothing at all to worry about and are purely cosmetic. According to the BRE, if the cracks are restricted to internal wall surfaces then they are classed as category 1 and can be dealt with using normal decorative methods. Within limits a certain amount of seasonal movement is to be expected anyway. If the situation worsens then it would be wise to set up some crack monitors but at this stage just fill, redecorate and don't worry.

 

[^woody^]

Thats not a crack indicative of subsidence. Looks more like an expansion/contraction crack.

Where is it in context of the ground floor - a bay, a corner, extension etc?

It most likley will crack again if filled, so use a flexible caulk, or take a strip of plaster off and fit some mesh across the crack and replaster

 

[puzzlebobble]

thanks for your advice Joe.

would you do anything about the possible crack in the wall in the basement? Or just leave it and keep an eye?

 

[puzzlebobble]

thanks for your reply woody.

in the context of the ground floor it is below a rectangular bay window at roughly the point between bay window and start of wall proper. the first photo shows a crack in the plasterwork of the bay window which is in roughly the same place.

 

[puzzlebobble]

Apologies for the lack of capital letters. My shift key is being temperamental.

 

[Shytalkz]

Forces that cause a crack will generally run at right angles to the line of the crack eg a vertical crack is due to horizontal forces. This one is predominantly vertical, which can suggest thermal cracking; however, rotation of the foundation to the front of the bay can result in similar cracking to the flanks, as the wall bellies outwards. Looks like it's on the line of a previous repair, btw.

That said, it's at a minor crack at this stage, so fill it as per Woody suggestion, which will let it self-monitor: if it reopens significantly, then would be the time to look at it a bit more closely and undertake some more investigation.

 

[^woody^]

But wouldn't a rotation crack show as being wider at the top or bottom, rather than an even width typical of predominantly horizontal movement? And I would not expect to see it this low down if the front bay foundation had rotated

If that is a bay, and the bay is or has moved in the way a bay might normally move, then there would be a similar crack on the other side of the bay, and possibly some paint flaking around the frame somewhere.

I wonder what foundationsnottipping would make of this scenario?

 

[puzzlebobble]

hi, aplologies I should have mentioned there's a hairline crack on the otherside of the bay. it runs from the corner of the window in a diagonal fashion about a third of the way down to the floor. Again no signs on external wall and on this side there is suggestion whatsoever of a crack at the basement level.

thanks

PB

 

[Shytalkz]

But wouldn't a rotation crack show as being wider at the top or bottom, rather than an even width typical of predominantly horizontal movement? And I would not expect to see it this low down if the front bay foundation had rotated

If that is a bay, and the bay is or has moved in the way a bay might normally move, then there would be a similar crack on the other side of the bay, and possibly some paint flaking around the frame somewhere.

I wonder what foundationsnottipping would make of this scenario?

If the bay is, say 2 storey and happens to be mechanically tied at the first floor level, then the split can be vertical and more or less even width, although, as this has a basement (hence lower down cracking - I agree that, if there was no basement, it would tend to be more obvious further up the building), it would be expected that a narrower continuation would be seen there, diminishing as it got towards foundation level. The pix seem to show that the basement crack is narrower, as best as I can tell by spinning the lappy on its side...

Familynottravellers - ah well, trying to second-guess his thought processes would require the use of a Kray super computer

 

[Shytalkz]

hi, aplologies I should have mentioned there's a hairline crack on the otherside of the bay. it runs from the corner of the window in a diagonal fashion about a third of the way down to the floor. Again no signs on external wall and on this side there is suggestion whatsoever of a crack at the basement level.

thanks

PB

Is the top of the crack further out into the bay relative to the bottom of the crack and is there a rainwater pipe on that side of the bay?

 

[puzzlebobble]

hi, aplologies I should have mentioned there's a hairline crack on the otherside of the bay. it runs from the corner of the window in a diagonal fashion about a third of the way down to the floor. Again no signs on external wall and on this side there is suggestion whatsoever of a crack at the basement level.

thanks

PB

Is the top of the crack further out into the bay relative to the bottom of the crack and is there a rainwater pipe on that side of the bay?

Hi Shytalks,
thanks for your reply. The top of the other crack is right at the corner of the window. The bottom is further into the house. Above the bay window is a thin balcony which is only the depth of the bay window. It covers the area outside this crack and continues over the front door (ie- it's sheltered from the rain.

However the balcony ends above the bay window on the other side (shown in the photos). The drain pipe from the roof is on that side and drains into my neighbours garden. I had noticed a small leak where the gutter meets the drain pipe but it's between second floor and roof. The leak is more directed towards my neighbours. there is a small amount of discolouration of the bricks below. I have been wondering how I can safely get up that high to fix it; and it doesn't help that it's directly above the wall between my house and the next.

thanks!

 

[Shytalkz]

There is a tad of rotation of the bay footing away from the main terrace from the sounds of it. The rainwater pipe is, I presume, cast iron all the way to the deck and into the ground? Does it serve the bays only, or the main roof of yours and the neighbouring property/ies as well?

Given the relative depths of the rainwater pipe and the foundations of the bay in the basement (Am I right in thinking that the basement extends out into the bay?), it's unlikely that any water escaping from the buried pipe serving the rainwater pipe would percolate down far enough to affect the bearing soils, so it's likely to be something else.

Bays are, by the nature of their construction quite fragile, as it is more window than masonry, so they can have a bit of a wibble from time to time, for reasons that are not always obvious. But strapping it back into the floor at both ground and first would give it a lot more robustness.

Can you post a pic taken from outside?

 

[puzzlebobble]

The pipe is certainly metal at the bottom. It runs straight into the ground. i thought it went into my neighbour's but it's actually on the boundary of the two houses in a gap between the garden wall and the house.

it serves the bays and roofs of both houses.

the basement does indeed extend out into the bays. sorry i should have made that clear. the photos in the basement are of the side wall of the bay.

I've taken a photo of the house but photobucket is behaving oddly- if you copy the link: "https://fileexchange.imperial.ac.uk/files/bd5fc8cb0c9/P1060061.JPG" into your address box you should get a photo. mine is the one with the hedge which needs trimming

 

[Shytalkz]

I can't believe you've been out at midnight to take a pic! Love the ghostly car too...

I digress. It looks from the pic that the bay (and the window above) drops down to the right. Is that so, or is that pic distortion? Can see the rwp, serves the main roof by the look of it (Edit: you said it did duh!). Looks to me that the pipework below ground either is or has been leaking. Dig it out at the neck below ground, see if there are any obvious defects; if so, or if it's cast, replace it in plastic to the front boundary, as well as doing the repairs as mentioned by Woody earlier and see how it goes thereafter.

Oh and trim the hedge