Raising an RSJ

[marlb]

Hi,

I am looking to raise the RSJ's in my Kitchen. The RSJ supports the original outside wall and was put in when the kitchen was extended. The work was done prior to me buying the house. I have had a structural Engr around who has said the RSJ that is in situ is sufficient to support the load. The trouble is that the RSJ is sitting lower than you would expect it too, in the kitchen. I cannot see a reason for it having been put in as low as it is and nor could the engr. So I want to support the walls and raise the RSJ's (one on the inner wall and one on the original outer wall) by one course of block. The span of the rsj's is just less than 3M long and the joists above the kitchen run at right angles to the RSJ's. My questions are:

1. Do I need to supports the original outside skin with Strong boys if so how many do you need in a 3m span.

2. How many acrow props do I need for the inner wall for a 3m span

 

[gasmick2]

Hi i did one once with a mate of mine and we used to old bits of steel 5" by 3" angle iron and cut out the joint all to where the rsj is going up to once that is in both sides on at least 4" then you could release the blocks on the r s j and then jack it up to the angle once its up to the underside of the angle you should be able to lever it out as the rsj only has a 1/4" to go up and with acros under it there should be very little movement you may even be in a position to leave the angles in and render over them etc

mick

 

[noseall]

if the ceiling/floor joists run onto the wall both sides, then all you need to do is prop these joists.

a pair of acros each side with a good stout board against the ceiling will suffice.

 

[marlb]

noseall, The ceiling joists only run into the wall on one side. The other side of the wall is the original outside wall and now has a pitched roof sitting on it and thus has no joists attached. I imagine I will need to use strongboys but I do not know what the spacing should be for block work. The house is 1930's block with 100% pebble dash.

 

[AtoZ]

if the ceiling/floor joists run onto the wall both sides, then all you need to do is prop these joists.

a pair of acros each side with a good stout board against the ceiling will suffice.

if you do that the wall could fall and the floor saty in place. your method relies on any gap between the top of the floor joists and the brick or block being filled with mortar or something else.
assuming a joist size of 8 inches and a block course size of 9 inches there is an inch for the wall to drop. once cracked the wall is damaged.

ive seen your way done lots of times with no problems but it is a gamble.


op
strong boys at worst will hold 45 degrees from any point you fit them but blocks are unlikely to fall because of the mortar and interference fit of the blocks.
they are ten bob to hire and the only problem is working around them.
i would use two maybe three but i cannot say for sure without seeing your wall.
it would be just as easy to pick holes in my method (but it would work easy)