Is my house going to fall down? - Victorian construction methods

[Ross85]

I've just purchased a mid-terrace, built around 1890 and I've taken all the original plaster off of the external walls as there was past evidence of damp and I wanted to make sure it was definitely old and there wasn't an ongoing issue. The house still had decor from 1960 so everything is coming out and I keep discovering cover up after cover up. Anyway...

I'm trying to understand how these terraces with the original, double height extensions are constructed. The entire house is double skin (Solid brick) but this changes on the half of the house with the extension on both floors, there's only a single skin on the back wall of the house, though the extension itself is double skin.

In the upstairs section of the extension at around the height its roof starts, the brick configuration changes from single skin, with the brickwork running parallel to the house, to the brickwork running perpendicular for one row and then the brickwork changes back to parallel and the wall continues to be double skinned to the top of the house (see cross-section attached and bottom of page for details). This means that the lead flashing for the sloping roof of the extension is flush to the house. Had the brickwork continued without doing this to the top, then half of the house would only be single skinned and I appreciate this would look strange amongst other issues.

My main question - is turning the bricks for one row and then building up as two layers to the top structurally sound? The overhanging section of brick inside the upper part of the extension is not supported by anything, there's just a roof shaped section of double brickwork visible from inside that appears to be suspended in space. See the two attached cross-sections I drew in paint (sorry, I know the proportions are off massively) if it helps clarify things.

*************
In the house cross-section the doorways into each floor of the extension are yellow, the lower red line is the lintel for that floor and the upper red line is where the brickwork changes orientation. The blue section is where I suspect the wall there was once removed, which caused the next floor to drop slightly over time (evidence via paintwork above door-frame) and is now concrete block.

The wall cross-section shows the lintel in red, with the door-frame in blue below. You can see the brick - unsupported on one side where the configuration is changed.

 

[88v8]

Hah!
130 years old.
Not going to fall down now.

The bricks that are corbelled out are supported by the weight of the bricks and roof above.
Like if you lie backwards on the edge of a cliff with your body hanging over, and someone sits on your legs.

It's good that you're getting to know the house. It will really feel 'yours' when you finish.

Ivor

 

[Ross85]

Thanks for putting me at ease, I just worried that it's a lot of stress on the lowest level of bricks. I was also extra worried because the upper lintel only runs halfway along the width of the extension and then it changes to a 1x1" piece of wood, which has lots of little bits of wood stacked on top to make it up to 2x2. This dodgy looking section continues across the house until it meets the window in the adjacent room. Said window has been replaced for a very large window in the past and its lintel (to my layman eyes) appears to be too short on one side and probably too small and as a result the brickwork below is fractured. The wall also bulges inwards slightly above the window, presumably linked to the lintel issue (see image attached where you can also see the strange wood section in the wall).

All of these factors combined, including a lower section of the extension being concrete block just compounded to make me fear for the structural stability of the property. We want to remove one of the lower, load bearing walls, which will require a structural engineer and I'll get him to cast his eye over everything.

 

[Ross85]

You can also see in the last image where the bricks ate raised above the window. This appears to be because the lintel (which appears to be 2x4 with the longer edge horizontal) has twisted in towards the inside of the room, I guess because of the corbelling on top of it.

I've pictured in my mind how I world replace a lintel if required but I'm struggling to do so on the upper floors, it's not like you can just put an acro prop either side like downstairs, or can you?

If lintel replacement is required, should I hold off having my parapet walls repaired? I'm worried that any movement caused during lintel replacement could dislodge the repairs.

In case you haven't noticed, I'm a bit frantic about it all, I'd anticipated certain repairs needing doing during the renovation but hasn't really accounted for this stuff in time or money.

 

[MikeG]

What's above that lintel? Is it eaves, or gable? BTW, there is plenty of end bearing there (150 is all you need each side, and 100 for small openings). However, that lintel needs replacing, and during that work the bearing bricks should be re-bedded.

 

[plasticpigeon]

I'm not sure if I quite understand where all the bricks you are talkking about are, but is there any chance that the single skin of bricks that you talk about could be one side of a flue on the back wall, where the chimney breast has been removed on the inside? I say this as chimneys often had a single skin of bricks on their outside. On my house that is the exact arrangement, I have a large flue from the old range on the back wall of the back extension, and the outer skin in only a half brick (single skin) thick.

Does the lintel above the window show on the outside? Could there have been an arch there originally?

 

[88v8]

Umm, past botching, and the sin of larger windows which are usually an uglification in an old house. plastic too, by the looks of it.

In my previous house the lintels were 9x9" cast in place. They were bedded no more than 6" and the brickwork in most the rooms was cracked, and where the lintels were exposed to the sun the expansion was shoving the walls apart - there was a crack running from each end of the south bedroom window out of the top of the gable.

It looks as if your lintel has 9" of bedding which should be OK. Has the brick beneath broken, or was a half brick inserted there? it's hard to see. The position of the closer in the next course down is suboptimal now, but as PP says, was there previously an arch? The load distribution would have been different.
However, the lime mortar is flexible so the stresses will have redistributed by now, based on that pic I wouldn't bother about it.

If the lintel were rotating, I would expect it to rotate outwards not inwards.

The length of wood in front of the lintel I take to be grounds for a curtain rail?
Don't quite follow your point about the timber across the extension. It was not unusual to bed a longitudinal timber in the thickness of the wall as a ground for fixings. There was one at least 12' long across the side of our staircase at ground-floor ceiling height in what was the external wall, but it was a 4x2". In those days - 1920 in my case - when they had properly seasoned wood, bedding timbers into walls wasn't such a problem as there was little or no shrinkage, but I wouldn't want to try it with modern quick-grown timber.

The bulging wall might have happened when the lintel was inserted. By which I mean, it's happened, maybe it was a one-off effect. How much is it bulged? Are there cracks in the horizontal pointing which would indicate continued movement?

If there is any question of replacing the lintel, yes I would hold off repairing the parapets.

Removing load-bearing walls sounds rather anti-Period. Personally, I deplore open-plan, knocking through, etc, so better not tell us too much about that :?

Older properties can indeed be a can of worms. There are people on this forum who have camped in their houses for years while they sorted out the results of mission creep. All good fun, in retrospect.

Ivor

 

[plasticpigeon]

Removing load-bearing walls sounds rather anti-Period. Personally, I deplore open-plan, knocking through, etc, so better not tell us too much about that :?

Ivor

I couldn't agree with this more, try and work with the property if at all possible. There is usually a very acceptable work around. Most problems are caused by poor quality modifications to original structure and fabric.