What supports outer wall with concrete lintels?

[Duncan4303]

Before steel lintels became available the inner leaf of a cavity wall is supported by an in situ concrete lintel. What supports the outer brick leaf? Viewed from outside bricks are resting [apparently] on the top of the doorway or window. Could anyone explain what the arrangement is please?!
We have some cracks on the inner wall radiating down from the edge of the lintel and a few thro the mortar only above the window outside. We are having the window replaced soon and the fitter was concerned that the bricks may drop away....
Thanks!

Duncan

 

[masona]

Can you see a flat metal bar under the facing bricks ?

 

[Duncan4303]

Hi,
No, nothing apparent without digging. House was built in 1960's or 70's.

Thanks,

Dunc

 

[masona]

You may have one of these type and that's why you cannot see it.

or this,

 

[Duncan4303]

Hi,
Thanks for the reply i will have a closer look. Its definitely concrete on the inside. Could be version one tho'.....
Ta,

Dunc

 

[TexMex]

Another method that was common in the past was to have a lintol (similar to that shown by MasonA set one course above the frame. Below it was a course of bricks that were just held in by compression. (a kind of struck arch with a practically flat curve). This leaves absolutely no external evidence of support of any kind. (as the lintol is sitting above the soldier course.)

The construction method consisted of placing an arch former in the doorway. (with a slight upward curve to the centre). Lay a soldier course on top ensuring nice tight joints. Knock out the wedges from the former to allow it to drop (by the height of the rise in the centre). Put pressure on the arch from above (by means of bearing down on it with your own weight. Hey presto, a flat arch. You then fit the iron lintol (which doubles up as cavity tray.) and continue to lay bricks on top.

 

[TexMex]

I've just remembered another technique that I was taught, many years ago (but never actually built myself) referred to as a "re-inforced brick lintol".

The method of constuction was to basically put a temporary support in the opening, and build straight across it. Every vertical joint over the support, however had a stirrup incorporated. The stirrup consists of a u shape piece of steel rod with the raw ends sticking up through the top of the joint. These raw ends had eyes preformed on them.

Through the eyes of the stirrups another pair of steel rods ran along the length of the wall extending across the opening either side (but on top of this first course). Dependant on the thickness of the wall more rods were also laid across (but not through the stirups) to give a bit more support.

These types of lintols were generally laid in keeping with the bond each side (ie, not a soldier course or brick on edge). Possibly just stretchers straight across the opening.

Once the temporary support is knocked out, you wouldn't see any thing from below. Just the bottoms of the bricks. If you were to rake out one of the joints from the soffit by about an inch, you may just see the bottom of the stirrup. Come to that, there may be a tell tale discoloration of the joints (from the rust).

Sorry if this isn't very clear. It's a bit difficult to explain without the use of a diagram. I can't find any mention of it on the web, but if you're interested I could probably draw it and scan it in.

 

[phykell]

Before steel lintels became available the inner leaf of a cavity wall is supported by an in situ concrete lintel. What supports the outer brick leaf? Viewed from outside bricks are resting [apparently] on the top of the doorway or window. Could anyone explain what the arrangement is please?!

That's exactly what mine was like though I've got solid walls and my lintel was wooden! I guessed that perhaps the original wooden frame was supposedly strong enough to act as a lintel for the outer "leaf", which was also held by strong mortar, to the lintel-supported leaf. Having replaced my window with a set of French doors, I took the opportunity to put in a couple of concrete lintels, one for each side. Not exactly easy but at least it's safe now.