Foundation Advice Needed

[MTN]

Hi,

 

I am digging out the footings for a outershed myself before getting a bricky in.  For context I want to build a breeze block double skin outershed, the breeze block double skin walls will be on both side and back of the outershed but the front will be breeze block and bricks. 

 

I started digging out my footings to roughly 450/500mm deep but along the boundary wall, I noticed my boundary wall was slanting (see pic) and I've dug out the 4 layer brick wall and then found out they are resting on slabs (see second pic) 

 

Now as this wall is no more and I want to bring my outershed to this wall, do I need to dig all the way down and beyond to my neighbours foundation? Or do I just got a little deeper? 

 

Just note that my street where is live is downhill so our back gardens are different levels.

 

Any advice on this would be greatly appreciated. 

 

Thanks in advance

Edited November 22, 2023 by MTN

[MTN]

Bump on this question. Thanks

[joe90]

It’s my opinion that those slabs are on your property!. Your side of their wall! Probably to retain your land/soil. All things being equal I would leave them there and pour your foundation against them. Depth depends on ground structure (solid is good) it’s only a shed (no offence intended).

[kandgmitchell]

Ideally you need to be down to the adjoining foundation level to avoid surcharging them. However the loads here are pretty small so not much would happen - just good practice. You mention Pic 2 but there's only one? Be careful of undermining that rear brick wall as it'll fall in. Dig that length in alternate sections to avoid that.

[MTN]

On 23/11/2023 at 16:19, joe90 said:

It’s my opinion that those slabs are on your property!. Your side of their wall! Probably to retain your land/soil. All things being equal I would leave them there and pour your foundation against them. Depth depends on ground structure (solid is good) it’s only a shed (no offence intended).

Yeah my only worry is as its soil underneath, how far is the ideal footing. Also I know it's a outershed but don't want to do the work twice had have issues later on down the road. 

[MTN]

On 23/11/2023 at 16:20, kandgmitchell said:

Ideally you need to be down to the adjoining foundation level to avoid surcharging them. However the loads here are pretty small so not much would happen - just good practice. You mention Pic 2 but there's only one? Be careful of undermining that rear brick wall as it'll fall in. Dig that length in alternate sections to avoid that.

 

On 23/11/2023 at 16:20, kandgmitchell said:

Ideally you need to be down to the adjoining foundation level to avoid surcharging them. However the loads here are pretty small so not much would happen - just good practice. You mention Pic 2 but there's only one? Be careful of undermining that rear brick wall as it'll fall in. Dig that length in alternate sections to avoid that.

 

Is it possible to go half way down vs all the way to the foundations level?

 

Also what do you mean my undermining that rear brick as I am taking that out and going about a foot below the foundation to build it back up again.

 

Lastly I've uploaded that 2nd pic. 

[kandgmitchell]

I was referring to the rear brick wall - the one with the fencing on. It looked like you were going to dig along it for the rear foundation.

 

Presumably you have no idea how deep their foundations are?

[MTN]

9 hours ago, kandgmitchell said:

I was referring to the rear brick wall - the one with the fencing on. It looked like you were going to dig along it for the rear foundation.

 

Presumably you have no idea how deep their foundations are?

I dig in front of it to see how deep the foundations of this wall goes. It is roughly 4 bricks down before I hit concrete

[MTN]

10 hours ago, kandgmitchell said:

I was referring to the rear brick wall - the one with the fencing on. It looked like you were going to dig along it for the rear foundation.

 

Presumably you have no idea how deep their foundations are?

I dug out in front of bricks in order to see how deep the foundations goes. And on the left hand side this is roughly 5 bricks under the ground but as the garden is on a slope, so the right hand side where the neighbours wall is must be at least 10 bricks down if the person who build the wall did it properly. 

 

My plan is to take this wall down to blelow ground level and make this wall into the back of the outershed with breeze/concrete blocks. 

Edited January 26 by MTN

[MTN]

On 26/01/2024 at 12:43, kandgmitchell said:

I was referring to the rear brick wall - the one with the fencing on. It looked like you were going to dig along it for the rear foundation.

 

Presumably you have no idea how deep their foundations are?

Bump on reply

[kandgmitchell]

I think this was answered in earlier posts - to avoid placing additional load on the neighbour's foundation you ought to be at the same level. If you stop your foundation half way down to theirs you will be adding extra loading. Whether that will actually have an effect in practice who can say. That'll have to be your choice.