supporting brickwork is it o/k ?

[edge]

I have had a new extension built and the roof is supported by two long RSJ`s
which the roof timbers rest on. Halfway up the roofline (purlins)
At the end where they rest onto the old existing brickwork, they are on concrete padstones but the brickwork beneath these padstones has been cut down vertically to the insides of the padstones to make a doorway through into the old part of the house. i.e. there is an opening of about six feet in between the steel joists. the brickwork on the outside of the joists , towards the outside walls tapers downwards to the eaves of the roof.

Should I weld another steel joist to span between the RSJ`s as they look a bit precarious as they are.

 

[masona]

Any chance of a photo ? I think you will need a structural surveyor for this

 

[edge]

Can`t do photo, but if you know what I mean it`s like the RSJ`s are standing on brick pillars, and It`s just that the brickwork beneath them only projects outward from the joists to one side. It falls straight down vertically from the inside of each joist.

Bob.

See this Sketch

 

[edge]

Masona, I have drawn an image in "word and sent it to admin in the hope they will attach it to the post.. Thanks for your reply .Lets see if it appears, I doupt they will do it before tomorrow, but i can only hope!
Again many thanks Bob.
____________________________
moderator

Guess again

 

[masona]

Should I weld another steel joist to span between the RSJ`s as they look a bit precarious as they are.

I think I got what you mean, are you thinking of putting a beam between the 2 RSJ's to stop them coming off the padstones going inward ?

 

[edge]

Yes, thats what I was thinking. I would be happier if I could see some sort of brace between them.
The roof joists are already braced accross the span with 4x2`s. on each joist.

I was always under the impresion that the stress from a load above was generated downwards in a triangular ppattern spreading down and outwards.? What do you think? Bob

Picture 2

 

[masona]

Right, there's no need to weld another steel joists (only if you wish to do so). You can use 2 x 6"x2" timber beam nailed together slotted in between the 2 RSJ's which is known as a collar beams or this is the way I would do it, on top of the RSJ's put down a 4"x2" or 6"x2" wallplate (flat way)depending on the width of your RSJ's and wedge it tight against the jack rafters and fix it together with screw, (between the wallplate & jack rafters) won't be easy or use twist scrap metal bracket (banging nails may break or loosen roof tiles above). Then a heavy duty joist hanger from the top of the wallplate over hanging down on the side of the RSJ's on both side for your timber collar beams at every 2 metre gap should be enough. This way nothing can move & everything is locked in the triangle formula
If I'm not clear on this, I will try & post a drawing tonight as my scanner need resetting !

 

[edge]

Thanks for the info, I`m not too sure I know exactly what you meen , and it would be great if you could post a scetch. I will read through again and try to get it . Again, many thanks. Bob
There is already a wallplate on top of the RSJ`s which the roof joists are birds- mouthed onto. I pressume a collar beam is two say 6" x 2" timbers screwed together to make a stong beam which form a wedge between the two RSJ`s? If so how do I hold this beam into the sides of the RSJ`s ? Is that where the Joist hangers come in?

 

[edge]

Thanks for the info, I`m not too sure I know exactly what you mean , and it would be great if you could post a scetch. I will read through again and try to get it . Again, many thanks. Bob
There is already a wallplate on top of the RSJ`s which the roof joists are birds- mouthed onto. I pressume a collar beam is two say 6" x 2" timbers screwed together to make a stong beam which form a wedge between the two RSJ`s? If so how do I hold this beam into the sides of the RSJ`s ? Is that where the Joist hangers come in?

Knowledge speaks wisdom listens

 

[masona]

If so how do I hold this beam into the sides of the RSJ`s ? Is that where the Joist hangers come in?

Cut the joist to the inside of the beam then swing it in (tighter the better & may have to cut a rebate depending the internal height of the RSJ's) and it rest on the RSJ's beam support. I didn't know you has a wallplate on top of the RSJ's so rest the joist hanger bracket on top of the wallplate. See the Picture
Is your wallplate on top of the RSJ's bolted through the RSJ's ? if not how is it fixed ?

 

[edge]

Seen picture. Got the idea now. Obvious when you know how isn`t it? I think this is a good idea, and saves me trying to get the welder up the ladder!!
(The wallplate is bolted through the RSJ) Many thanks Bob

 

[edge]

Seen picture. Got the idea now. Obvious when you know how isn`t it? I think this is a good idea, and saves me trying to get the welder up the ladder!!
(The wallplate is bolted through the RSJ) Many thanks Bob

 

[masona]

The wallplate is bolted through the RSJ

That's fine, the joist hanger will stop it coming off the RSJ's and no need to double the joists together, just do a few single one. You could make a storage space shelf up there if you want !

 

[edge]

It just so happens that I`ve got a 9" x 2" foor joist spare which I can cut down to fit the RSJ. This is long enough to make two spars, that should be enough I think because at the gable end of the room, all is bricked in O/K.
Thanks again Masona.