Structural Question - Any engineers/builders about?

[hyphen]

Old house question. On a house such as the sample one one pictured below: there is a ground floor front projection so the 1st floor front bedroom is smaller than the longer living room.



The way they used to do this at the time (I think), is to put brick pillars in the living room with wood going across them, so the first floor brickwork is built off it (floor joist also join these beams). A crude illustration below:



These houses have been standing for 100 years, so clearly it works fine. But I am curious as to:
1) how much load can these wooden beams take
2) and if it would meet todays standards? What would be the equivalent RSJ sizing.

Edited by hyphen on Thursday 8th June 15:18

[bobtail4x4]

no you "wooden" use wood nowadays,

as to size of steels? it depends on the opening size,

[hyphen]

Do you know what the load capacity of the old method would be?

[Alucidnation]

A builder I know has just had to shore up and rebuild most of the front of a house built like this as it started to push outwards, mainly due to the timber that was used as support.

[TA14]

Alucidnation said:

A builder I know has just had to shore up and rebuild most of the front of a house built like this as it started to push outwards, mainly due to the timber that was used as support.

The term the OP is searching for is bressummer beam. They'll take a lot of load when new but tend to rot and sag causing the brickwork above to collapse.

Aluc's case is probably where the beam has rotted, sagged a little and then rotated pushing the brickwork out as well as down. In the most part they're plastered and totally hidden so a precast concrete lintol would be the obvious choice.

There are so many variables that there's no one size fits all. Best to just post what you mean instead of trying to find a universal solution.

[hyphen]

Thanks- didn't know there was a term for it.

I just want to know what the 'lot of load' is, i.e. if there is a recommended maximum load when they are in good condition.

[TA14]

Try load in Newtons = 6 x b x d x d / l for a ball park figure where b is the breadth of the beam, d is the depth and l is the clear span. There are many variables and you could easily be out by a factor of two but it will give you an idea. FWIW i think that the beams in your example would most likely fail for that span.

[wolfracesonic]

You can often see these bressummers exposed when the fronts of shops in terraces are having their fronts refurbished. A structural engineer would now specify 3 305 x 102mm UBs seated on unobtanium pad stones with the foundation for the pillars taken down to the centre of the earth. Probably.