Do I need an RSJ (Is my house going to fall down)?

[jimmypeaks]

During rennovating our house we bought about 3 months ago, I discovered a bit of 25 year-old diy where a dividing wall used to be between the living room and the dining room. They've put in a 9 x 3 wooden beam rather than an RSJ, and this is supporting a brick wall above:

Untitled

• jimmypeaks
• 30 May 2008
• 1

My question is, is this safe? There's no signs of any craking in the wall above, and it's been like this for 20 odd years. I spoke to one structural engineer who said it'd probably be alright, but wants 200 quid to say for definite, and another couldn't believe the house hadn't fallen down.

I would really appreciate any advice on this.

thanks
james

 

[Deluks]

All 'proper' brick then? Not lightweight blocks?

In any case I'd be swapping out for a steel beam.

If there's space at either end for a decent bearing, you could just bolt a PFC (C shaped beam) on either side of the 9x3, making a steel/timber/steel sandwich.

Relatively simple job, using M12 bolts and single sided timber connectors.

 

[Bowness72]

You could probably do that anyway, without needing to extend onto the walls at each ends. Although the shear stress at the ends of the timber would need to be checked by an S.E. If the brickwork above is solid it may be arching anyway and not putting much load onto the beam

 

[willroy]

Is the wall above supporting anything?.If yes a rsj is needed.A structual engineer can come in charge a few hundred quid and tell you to put a rsj in which you were going to do anyway.Look at the wall above if it does not support anything take it down and put a stud wall up.It may be supporting a purlin . I have recently undertaken something similar with a wall upstairs which i removed and supported a purlin above with a rsj. i the lowered the ceiling on the landing to below the level of the steel to give me one flat ceiling(old house 9ft ceilings)

 

[Shytalkz]

With a wall on it as well as floor, a timber that size would undoubtedly be overstressed by modern calc methods. However, that aside, timber will suffer from creep deflection over time, even if adequately sized, as long as the loading is applied. Hence why these days it is not normal to go putting masonry on top of timber beams.

In the apparent absence of any cracking to the wall above, there is obviously some arching going on, but one day that won't be enough and cracks will develop. If you're doing a comprehensive refurb, as appears to be the case, it's not worth spoiling the ship for a ha'p'orth of tar, so I personally would go for a steelie in there. Size dependent on loads - tell me the spans of the two floors, the beam span and the height/thickness of wall above and I'll tell you what you need (but not today...!).

 

[Bowness72]

Tut Tut Shytalkz, offering to carry out design for people. I was recently notified by the moderators not to do that and swiftly followed up by a similar comment from yourself. Although don't get me wrong, I'm sure the answer would be ok. Also, you didn't ask the original poster to tell you if there was any roof load being applied to the wall above.

 

[Shytalkz]

Petard. Check.

Rope. Check.

Suitable branch. Check.

Up I go....

 

[chessspy]

OK, the timber is holding the wall up, but it ain't right is it?
Best change it and have done with it. Don't forget to put a padstone under the ends of the steel to spread the load.
I'm sure you know how to support the joists above and make sure the load is transferred below etc. whilst you are changing things over, and it should only be a days work for two strong lads.
It occurs to me that you could bolt a deep u steel to the sides of the existing timber 9x3 as long as you make sure it is landed on at least 4" and a pad at each end.

 

[Shytalkz]

Nope you're right Chess, now he's uncovered it, it would make sense to do something about it; and, as you suggest, a channel section, say 150x75 either side with 100mm bearing onto an engineer brick would suffice.

No doubt Joe will be along to suggest otherwise though...

 

[Deluks]

Yep, great idea Chessspy. Suprising no-one else mentioned it in previous replies.

 

[chessspy]

Hi, delux,
That my friend, is because I is de MAN!

 

[joe-90]

Nope you're right Chess, now he's uncovered it, it would make sense to do something about it; and, as you suggest, a channel section, say 150x75 either side with 100mm bearing onto an engineer brick would suffice.

No doubt Joe will be along to suggest otherwise though...

I'm waiting for these marvelous SE calculations worth £300+.

Don't forget to show your working out.

 

[chessspy]

E=MC2, - 3.14159 Root e +i
=
BOOOMMMMMM!!!!!

 

[Shytalkz]

Joe: dead bear, arse; your head, go stick it up there...

Be a good boy now and go and pontificate over some other subject about which you know the square root of f**k all.

 

[chessspy]

Now now, children, tut tut.