Piers for RSJ on Block & Beam Floor

[brennan2470]

I have a detached double garage with a block and beam floor and intend on installing an RSJ to act as a mid span for new joists I’m going to fit alongside the existing trusses to create a storage floor

I am about to instruct a structural engineer to spec everything up but before doing so (and forking out for it) I wanted to get a sense of what the likely options will be to support the 6m long steel, given the walls are single skin and from what I read, you can’t build brick piers directly on top of b&b floors.

If the S/e is likely to come up with some elaborate and hideously expensive suggestion given these limitations then I’d rather not bother, and just leave it here.

Any ideas? Thanks

 

[noseall]

I have a detached double garage with a block and beam floor and intend on installing an RSJ to act as a mid span for new joists I’m going to fit alongside the existing trusses to create a storage floor

I am about to instruct a structural engineer to spec everything up but before doing so (and forking out for it) I wanted to get a sense of what the likely options will be to support the 6m long steel, given the walls are single skin and from what I read, you can’t build brick piers directly on top of b&b floors.

If the S/e is likely to come up with some elaborate and hideously expensive suggestion given these limitations then I’d rather not bother, and just leave it here.

Any ideas? Thanks

The beam and pier will need its own foundation. B&B floors are not load-bearing, no.

 

[freddiemercurystwin]

Seems like an odd construction, B/B floor in a single skin garage, are there no piers?

 

[brennan2470]

The beam and pier will need its own foundation. B&B floors are not load-bearing, no.

I would hope it’s load bearing considering I could fit 4 ford fiestas in it if I tried hard enough!

I’m assuming a foundation for a pier when you have a b&b floor will be an absolute headache?

 

[brennan2470]

Seems like an odd construction, B/B floor in a single skin garage, are there no piers?

Yeah there are piers but they are staggered along each of the walls so don’t line up at all. I believe most new build garages are b&b floor

 

[noseall]

I’m assuming a foundation for a pier when you have a b&b floor will be an absolute headache?

It's not ideal, especially if the floor beams are close together (blocks laid lengthways).

 

[brennan2470]

It's not ideal, especially if the floor beams are close together (blocks laid lengthways).

Balls… Any alternatives (not engineered joists)?

 

[freddiemercurystwin]

It's not ideal, especially if the floor beams are close together (blocks laid lengthways).

Provided a B/B is specified correctly then it will be more than adequate for a garage floor, or any other load bearing scenario.

 

[cdbe]

Bear the beam on the existing wall. I'm not sure it will carry 4 ford fiestas but I think it'll manage a bit of storage.

 

[brennan2470]

Provided a B/B is specified correctly then it will be more than adequate for a garage floor, or any other load bearing scenario.

I’m lead to believe that b&b floors have a higher specification in new build garages than in homes. 2.5kn/m2 and 9kn point loads. Bear in mind the RSJ will probably weigh 160kg, then the weight of the brick piers, then nearly a tonne of timber and chipboard T&g flooring. That’s before I’ve even stored anything up there

 

[brennan2470]

Bear the beam on the existing wall. I'm not sure it will carry 4 ford fiestas but I think it'll manage a bit of storage.

Single skin wall both sides. Does have piers either side but they don’t align so I can’t notch into them. I’m lead to believe that with appropriate sized padstones I could still have an RSJ supported by two single skin walls, or am I grossly mistaken?

 

[cdbe]

Inside your average house - probably one end of about a third of the beams in the country are sitting on single skin walls.

 

[brennan2470]

Inside your average house - probably one end of about a third of the beams in the country are sitting on single skin walls.

That is reassuring to know. I hadn’t realised that. Presumably if my garage has multiple piers around the perimeter then the footings must be wide enough for a second skin of bricks to sit underneath the RSJ and increasing the seating from 100 to 200mm if I wished? Or do you think they would literally scrimp every last bit and only widen the footings where they intended to build a pier?

I also notice you said “one end”. Is it only possible to have one end of an RSJ sitting on a single skin and not both?

 

[tony1851]

If you're using the ceiling for light storage, I can't see why you can't sit the UB on the existing single-skin walls. If the loads are not too heavy, you can dispense with padstones and set the beam on steel plates as spreaders - this could avoid messy cutting out of brickwork.

If you tell your SE what sort of load you consider putting up there, s/he should be able to check fairly quickly whether its feasible to use the single-skin as support, without jumping into some elaborate Heath-Robinson scheme. The load-carying capacity will depend on the height of the wall above the foundation, the type of brick, and the spacing of the piers.

The piers are intended to reduce the 'slenderness' of the wall and hence to allow it to carry a little more vertical gravity load, and also provide a bit of extra stiffness against wind load.

 

[brennan2470]

If you're using the ceiling for light storage, I can't see why you can't sit the UB on the existing single-skin walls. If the loads are not too heavy, you can dispense with padstones and set the beam on steel plates as spreaders - this could avoid messy cutting out of brickwork.

If you tell your SE what sort of load you consider putting up there, s/he should be able to check fairly quickly whether its feasible to use the single-skin as support, without jumping into some elaborate Heath-Robinson scheme. The load-carying capacity will depend on the height of the wall above the foundation, the type of brick, and the spacing of the piers.

The piers are intended to reduce the 'slenderness' of the wall and hence to allow it to carry a little more vertical gravity load, and also provide a bit of extra stiffness against wind load.

Thanks. I’ll relay this to the s/e when I find one. The load is going to be circa 2 tonne however the RSJ will only act as a mid span for the joists, so the existing wallplates will be doing a lot of the work too.