The Brew Cabin

Posted: **Tue Feb 02, 2016 11:51 am**

Hi,

Great web site!

I have searched for help on my problem but could not find a detailed answer so here is my first post.

I have started excavation for block paving at the front of my house to discover that the foundations are three bricks below the DPC. House is built on chalk. Original tarmac surface was 1 brick below the DPC in one corner slopping towards the drive up to the house. The start of the drive from the road is 1:5 levelling out to 1:20.

My plan is to "haunch" the edge of the foundations to give a sold bed for the first two rows of 160mm wide block paving so that block are not half over mortar and sand. Once cured the first two rows will be bedded onto 15-20mm of Class II mortar. Considering haunch mix of 6gravel/3sharp sand/1cement. Alternative mix could be 8sharp sand/1cement. The foundations at the front of the bay window are slightly higher that the rest so will probably need to grind/chip the edge down to get any sort of fall and keep 150mm below DPC. From the bay window the surface needs to fall more steeply than elsewhere because it is the closest to the drive down to the road. Ideally I would have like to have had a fall from the front of the house out ward along the bay window but this is not possible with out removing the top of the foundations at the front of the bay.

So is haunching the edge of the foundations ok and to what depth with the 6/3/1 mix or 8/1 mix?

Is a 1:5 drive Ok for flexible block paving?

Presumably I need to lay the paving so that it sloped away from all edges of the bay?

Not sure how to add a picture!

Thanks

PS
Here is a link to the photos:
https://goo.gl/photos/FY6yw63rpjmtPrYS6

Posted: **Tue Feb 02, 2016 10:09 pm**

Could you make a gravel border around the bay window so that the paving is not against it.

It is hard to advise without images. Photobucket seems to be the only way to post an image on the board.
Some posters share a link to a flickr or picasa album with the relevant piccies.

Posted: **Wed Feb 03, 2016 10:28 am**

Hi
Thanks for your reply.

The edge of the foundations is not straight and varies by at least six inches so would probably need to squared off with concrete and edging to contains the pebbles. The foundation edge looks very rough and does not appear to be a particularly strong mix (1930s build). There is just enough height to the DPC for blocks and mortar which I think would look better if that approach is ok??
Originally uncovering foundations "spooked" me and I was worried about weathering and so forth on the integrity of the exposed foundations (I am a born worrier). A google search reassured me exposing them was OK. I presume that laying fresh concrete against the foundations will not damage them?

Here is a link to the photos:
https://goo.gl/photos/FY6yw63rpjmtPrYS6

regard
Adrian

Posted: **Wed Feb 03, 2016 1:29 pm**

I'd run a diamond blade del as you can the width of your edging blocks but ay least 200ml and break out enough leaving you a neat edge and lay away.

Posted: **Wed Feb 03, 2016 8:37 pm**

I'm going to go out on a limb and say that its not footings have you tried digging down the side of the concrete you may find its only 100-150mm thick have a little dig and if you find its only thin dig a spades width under the concrete and you may find more brickwork

Posted: **Thu Feb 04, 2016 12:00 am**

Thank you for your responses.

Cutting the edge of the foundations to a depth of over 200mm sound like very harder work compared to putting in some shuttering and pouring concrete. The foundations do not look to be a particularly strong mix especially when compared with the concrete running up the drive which I am not looking forward to jack hammering out. I would be concerned that cutting could dislodge more than intended.
There is one section which is particularly wide that could be a candidate for cutting. The section under the bay window does look as if I could pick out the stones from the edge with little resistance.

I have dug down at a corner of the house to replace some drainage so I am reasonably confident that the foundations are 3 bricks down from the DPC and that their is not a skirt above the foundations. Also if it was a skirt it would have a straight edge and not something that has been thrown into a roughly dug trench. I believe that this is not uncommon for houses built in the 1920s and also that they are likely to not be that deep. Digging into chalk results in large lumps of chalk and flint being dislodged so getting an trench with straight sides is not easy and levelling the site is also not easy. When wet you end up with 1 inch of chalk stuck to the bottom of your boots. Not to mention the voids that appear beneath a lump of chalk that you have just removed (I am amazed the house is still standing).

Posted: **Thu Feb 04, 2016 10:15 am**

Didn't say break out 200 deep. I said " make it at least 200 wide." The cut would break off clean then with a hefty thump of a persuader ( heavy sledge )

Posted: **Fri Feb 05, 2016 11:04 am**

Hi seanandruby,

I do apologise for misunderstanding your reply.

The foundation width varies from 200mm to 320mm along the house wall except in the corner with the bay where it is 430mm. We would like to use blocks 160mm wide and 50mm deep with the paving level the recommended 150mm from the DPC sloping way from the house. This would be possible with a thin mortar bed on the foundations for the first two rows (320mm) but may require about 10mm reduction in height of the foundation at the front of the bay where the foundations are slightly higher but would fall away more towards the drive.

Two new builds behind us had serious subsidence which I believe was in part due the chalk or possible ancient diggings. Hence my concerns about disturbing the foundations.

The Brew Cabin

Foundations near dpc