Foundations

[Pedrx]

Hello: I would like to widen the aperture, presently a window, in a 9” solid, lime mortar, red brick wall, from 3ft to about 7ft to make a doorway. The aperture will be extended in one direction only towards the corner of the building leaving about 9” of wall at the corner upon which to support that end of the lintel.

A builder who has viewed the job proposes merely to remove that section of the wall and fit the lintel.

But is this correct procedure? It was once a window hence the weight above would have been distributed evenly along the foundation. But with 7ft of wall knocked out to the floor there will be 7ft less of foundation to take the weight.

Above the lintel will be a couple of brick courses, and then the wall plate supporting the slated pitched roof. The foundations are solid random stone.

Also, what type of lintel will be necessary to support the wall plate and roof? There is little weight in the brickwork but nor is there enough depth of brickwork for the bricks to form any integral strength.

I suppose it would be best to dig an inspection hole either side of the proposed aperture to see what the foundations are resting on.

Yes, I will get a decent builder, get the planning officer, get a structural engineer if necessary but, in the meantime I would like to learn what I can about the job, if only for the interest value, and from past experience even recommended tradesmen have sometimes been less than satisfactory.

Will be glad of any advice. Thank you.

 

[RedHerring2]

As no-one else has made any comments, I'll offer mine, bearing in mind I'm just a DIYer.

I think you'll struggle to get as narrow a pillar as 9" in a rubble built wall.
There may be little or nothing in the way of foundations as we understand them today, in your situation. There won't be the normal amount of weight on this lintel that you'd normally expect, becasue, I'm assuming that this is a bungalow, perhaps with dormer windows upstairs.

The lintel specification may be unusual 'cos of the thickness of the walls, I'm guessing 2' thick or a little more.
I made my own, in France. You can see int his post the reinforcing that went into each one. They were cast in situ:

//www.diynot.com/forums/viewtopic.php?t=210516

I did consider several side by side through the thickness of the wall.
In your case I would have thought that pre-stressed concrete lintels would suffice, but your BCO, or if neccesary SE will advise.

You'll probably have to remove all the stonework, right up to the wall plate and replace it after the lintel is in. Your builder will advise.

Edit: Sorry, just reread your post, it's red brick, not rubble stone. So either a couple of concrete lintels or a metal lintel may suffice. So builder will advise and BCO or SE will decide.
In which case it may be possible to insert a lintel without removing the rest up to wall plate.
The comment about 9"wide pillar may still be a little too narrow for the BCO to accept. Your builder will advise and then the BCO will decide.

Yes an inspection of foundation may be neccesary but this is not too arduous.

 

[^woody^]

There is nothing wrong with what the builder proposes to do. The foundations are not an issue and wont need to be checked

Any standard lintel will do if it has the suitable depth to fit in below the plate

 

[Pedrx]

Thank you Red Herring and Woody. Am happy with the lintel issue and will check the 9" pillar thing.

I know it's tiresome when people who ask for advice don't seem to accept it but just bare with me on the final question.

Woody, you say the foundation is not an issue when making a 7' apperture in brickwork: as the weight is no longer on this 7' of foundation but transferred to the remaining, in this case 14', does that not mean there is about 33% extra load on the remaining foundation?

I can understand this idea where there is 7' min of brickwork below the apperture to transmit the load at 45% back to the foundation but surely that is unusual?