Hello
Our loft company has done a poor job installing the RSJs on our loft conversion.
They’ve used these thick steel plates about 100mm x 400mm x 8mm thick. They’ve put minimal bricks underneath the steel plates just 400mm, possibly not used a decent mortar to set the bricks and plates in position. Where they didn’t need to build up the base with bricks they have not scraped back all the original 1930s black dust cement that was on top of some the original bricks and layed the plates on that.
However, my main concern is that the RSJs sit quite close to the edge of the plate in places. The length is fine, but if you imagine the steel plate is 400mm wide you’d expect the RSJ to be roughly in the middle and have 100mm each side. However ours has 190mm one side and 10mm the other as they didn’t line them up very well. Is this a major problem?
Thanks
D
Are you a tradesperson and able to answer this question?
The plate and its position to the steel beam has no bearing on the structural integrity. Its sole purpose is to distribute the load evenly down to the brickwork and stop the beam from creating load points that would lead to cracking and crumbling of bricks. Did you or the builders use a structural engineer? If so, check the specs to see they have been followed.
Answered19 June 2023
7
Anonymous user
Normally the plate should be at least 20mm thick and normally about 600mm long hence the word spreader plate should be ideally middle of plate but sometimes can not be achieved also the plates can be laid on old brickwork with new mortar
The steel plates should conform to the engineers design along with the RSJ bearing in either end, there should be a minimum bearing of the RSJ and I would expect this to be at least 100mm on either end ideally more.
The steel plates should be bedded on New mortar in order for them to have stability and a good bearing for any loads applied.
Where the steel sits is absolutely important to the structural integrity .
Firstly you must have a structural engineer in . They will give you the calculations to tell you what steel you need . The building inspector will need his calculations as well as seeing the steel to pass building regulations . Once the size of the steel has been chosen it must seat in the middle of each pad stone . Each side must have a minimum of 150 mm each side . This makes sure that it is spreading the load evenly around the rest of the wall .
