A reader's General Construction question: Propping wall?

Sid C.   from   Durban , South Africa   had this Propping wall question.

Hi Bill. Great site. My problem is finding the best solution to propping roof trusses.I am taking out existing windows and adding larger sliding doors etc.Ie making the opening larger.I have to add new bigger lintels and knock out a bigger opening on main load bearing wall.
Can i prop on inside of wall under truss...will that be sufficeint?
The other problem is how do i stop the wall section above existing lintel from caving in(besides propping)bearing in mind i have to remove a few rows higher than before because new sliding doors are going to be higher than the standard 2,1m.Thanks Sid

Bill's reply

Hi Sid, I wouldn't bother propping the trusses at an internal wall, but I'd definitely run a row of props with a decent top plate as close as practical to the outside wall.

• Make sure there is something solid up there like a decent batten between the plaster and the trusses, otherwise cut the plasterboard ceiling to make sure that you are holding the trusses, not just the ceiling sheets.
• Regarding the wall over the new openings, if it is only a few courses of bricks, just remove them all.
• If it is worth trying to save them, then you will have to prop the brick/masonry, with a few props with needles going through the wall, I have not done much on this type of work on the site, but if you look at a section that I have about brick underpinning you will see a sketch

Cheers Bill.