Bay window tilting away from front wall

[HairLoss]

Hi,

The single story bay window on my Victorian terraced house is beginning to tilt away from the front wall. Neighbours have said that the soakaway for the downpipe that is within a few feet of the bay window is the likely cause and that others have added an extension to the down pipe so the water is taken to the front of the small forecourt and away from the house.

Does this explanation sound feasible?

If the soakaway has washed soil from under the bay window foundation then should I replace the concrete covering the forecourt with a permeable paving solution so that rain water can gently wash soil back into where the soakaway has washed it away?

 

[Notch7]

If the foundation is sinking, it needs underpinning.

In a house wall, a common way to strengthen a foundation is to dig out a metre cube, fill with concrete, when set dry pack.
Then dig out the next section and repeat.
Im not sure if you can do that with a bay though.

Foam injection can be done to correct subsidence, but It may be too expensive for a small job. Ive seen it done on a huge house that had dropped about 4".

 

[bobasd]

you need to plan the future arrangements for water disposal before attempting anything with the bay itself.

your, far too small, discharge pipe from the bay roof has been dropped independently, it should have been tied into the old CI down pipe like your neighbour has tied into it.

attempting to sump the discharge water anywhere in your little forecourt will probably undermine either the garden walls or the bay - some householder's pipe the discharge to the front garden wall and tunnel through the garden wall just above pavement height to discharge over the pavement.
neither the Council nor the Highway authority approve of such arrangements but they were often used in the past.

OP,
why not provide photos of the actual gap(s) thats developing outside on the bay, and pics of any cracking or out of plane and level inside surfaces?
plus a shot of the small forecourt?

above the main elevation opening for your bay there is a wood lintel called a Bressummer beam - check it for level and any obvious damage.
there are a number of obvious other issues in your photo but for now - the bay.

 

[HairLoss]

Thanks Bobasd,

I didn't know about Bressummer beams, learnt something new!
I am away for a few weeks but have some pics on my phone. Unfortunately none show the gap outside at the top which is about half an inch on the drain pipe side and it has pulled the lead flashing out of the brickwork there, but it is only a small crack at the other side.

 

[bobasd]

the crack in the ceiling is the position of the Bressumer beam.
even if the timber beam is not water damaged its now possibly being exposed to decay.

a SE will have to make the calls on your bay - worst case will involve propping and pinning, and a re-build of the bay and any affected abutting walls - the floor will also have been disturbed (fwiw: there's probably existing damp problems in the lower panels and flooring).

just curious - is this an empty house? a bought as is at auction?

 

[HairLoss]

Yes, a bought as seen repossession property.
I have had subsidence in other houses which looked far worse then this so I an surprised we are talking rebuild and underpinning.

 

[bobasd]

you will be even more surprised if your damaged bay elevation begins to affect either of your neighbours.

re-build is a "worst case" not a first case - you have three large openings and very little brickwork in your front elevation.

check out which way your floor joists run on both levels?
check if any knock-throughs have previously taken place in the property?
notice you are on a slight forward slope?

i'm surprised you dont have a cellar.

its possible that your Victorian bay has Differential Settlement besides the other difficulties.

 

[^woody^]

Excess ground water can cause foundation movement, but so can several other things.

Once saturated ground returns to normal, ground tends to swell back up and this pushes the foundations up and closes any gaps in the wall.

But you need someone qualified to assess this - the cause and the remedy.

 

[oldbutnotdead]

That concrete surface on your front yard- is it a thin skin above the original (probably) glazed blocks or earth or is it a proper 4" slab? How much traffic is there on that road, have the council put speed humps in?
Have you put a spirit level up against any walls yet to see what is vertical?
It is possible that your bay was chucked on to the house well after it was built (there a quite big differences between it & your neighbours)- if that's the case you may well find there are no foundations (or very puny foundations) & that's why it is moving (don't ask me how I know this). Any plaster cracking or other evidence of movement in the room above the bay?
Given the structure of the thing (lots of solid stone) you might be able to use micropiles- loads easier and less intrusive than digging out and throwing cubes of concrete at the job. Would agree that getting a structural engineer to have a look (ideally a local one familiar with local ground conditions) would be a good investment.

 

[HairLoss]

"That concrete surface on your front yard- is it a thin skin above the original (probably) glazed blocks or earth or is it a proper 4" slab?"
I haven't looked closely but it looks like there is only soil below and probably only a few inches thick.

"How much traffic is there on that road, have the council put speed humps in?"
The road is not particularly busy and there are no speed bumps.

"Have you put a spirit level up against any walls yet to see what is vertical?"
I haven't used a spirit level but walls appeared to be properly vertical and floors had no noticeable slope.

There is no plaster cracking in the room above unless the wallpaper is concealing something and I checked all the external brickwork carefully and there is no sign of movement at either side of the bay or above the bay.

Thanks oldbutnotdead.

 

[KenGMac]

How long have you "owned" the property? if for some time then an Insurance claim could be made?

Any idea of what the ground is below the property? is it a clay? or Loam, or ???

Are there any large trees within 20.m of the property? if so what species?

As for repair considerations [depends on para 2 above] check out Shire piles + Uretec

Are the external sills level?

In many, many cases the foundations for the bay are vastly different from the main properties walls?

 

[bobasd]

OP,
why not prep. the bay situation before any SE arrives on site - what i'm suggesting below will give you more insight and the SE a clear view shot at things.

the concrete forecourt is a 40mm-50mm skim. remove all the concrete.
remove all render on the lower panels and plinths of the front elev. and bay.

inside - open up the ceiling following the crack line - its possibly plaster laths.
open up back to brick the cracked LH wall panel shown in your pic.
dont disturb any of the coving.
remove all low level plaster and skirting from below the window boards of the bay - go back to brick.

remove any floor coverings in the GF and FF rooms.

send this thread and any photos to give any SE a heads up prior to a site visit.

inquire if the SE would like a foundation inspection pit dug ready for a site visit? (best dug at the junction of the bay and the house - but the SE's call).

 

[HairLoss]

Hi KenGMac, to answer your questions:

"Any idea of what the ground is below the property? is it a clay? or Loam, or ???"
Geology report found online says the soil in this area is loamy-clay.

"Are there any large trees within 20.m of the property? if so what species?"
Nearest trees are on other side of the road and about the same height of the house.

"Are the external sills level?"
Yes.

Thanks for names of Shire piles and Uretec, micro-piles are clever solution.

 

[HairLoss]

Thanks BoBasd,
I had it in mind to do a similar revealing of the Bressumer beams and the base of the bay window and surrounding brickwork as until that is done a reliable diagnosis cannot be made.