What are these lintels, please!?

[Grandad Gaz]

I have looked on the interenet but, cannot find them listed anywhere. I rang the architects yesterday. They were polite but unhelpful, probably because we had a slight disagreement over the cost of a few alterations to the plans. We paid up under protest but that's a different story!

We have to have a very shallow pitch roof to enable us to get under the existing brick detailing to the main roof (conservation officers wisdom), so depth is important.

The cavity specified is 4". Two main openings, one at 1800mm the other at 3000mm. because of the wide cavity, we have to have two lintels for each opening. The external ones I can find. they are standard (SB/K)

What I can't find are the others:- 125 x 125mm DP CN24 lintel and a 125 x 125mm DP Keruing lintel.

Any ideas welcome Thanks

[herbialfa]

Typo???

[Globulator]

Ring up your building inspector: he would have had to approve the plans and will have alternate ideas.

If that fails you'll have to talk to a structural engineer.
In my experience, architects suck.

[Qcarchoo]

It appears that these lintels are timber, C24 referring to stress graded softwood, Keruing is a type of hardwood.

[Busamav]

CN is usually a Catnic lintel ref .

Sorry but I do not know the exact type as I usually spec IG Lintels

Edited by Busamav on Thursday 16th September 01:15

[ncs]

Qcarchoo said:

It appears that these lintels are timber, C24 referring to stress graded softwood, Keruing is a type of hardwood.

Spot on.

[mrmaggit]

Catnic don't have a reference CN24, though they do have a CN23 which is for timber framed buildings.

[Busamav]

mrmaggit said:

Catnic don't have a reference CN24, though they do have a CN23 which is for timber framed buildings.

definitely is the timbers then .

[eps]

Do you have any calcs to back up the lintel choices? i.e. what's the load on them and the span?

[eps]

Keruing is a type of timber... hardwood.

http://www.trada.co.uk/dir/products/71BB3166-3A7A-...

I guess you're going for look over function.

[eps]

DP _could_ be http://www.dptimberdesign.co.uk/

I could check the timber for you... but would need to know the loads.

Have you got other externally visible timber lintels in the property already?

I would have thought it better to use a Catnic or IG and then face it with timber..

[Grandad Gaz]

Many thanks for the useful replies

Timber sounds like the answer! With one of the spans being 3000mm it is not possible to get a catnic less than 250mm deep.

Loading is minimal. Just a very low tiled roof as shown here:

[Busamav]

I must admit to being surprised that the 125 timber lintel will span 3m , just ensure you have a very positive fixing at the head of those rafters.

Lets hope the doors still open after a few seasaonal changes

[andy43]

Grandad Gaz said:

Many thanks for the useful replies

Timber sounds like the answer! With one of the spans being 3000mm it is not possible to get a catnic less than 250mm deep.

Loading is minimal. Just a very low tiled roof as shown here:

Think you need to speak to the architect. A 3m span using a chunk of wood as a lintel sounds a bit dodgy, even if it's posh hardwood. My guess is it's supposed to be a CN23 timber FRAME lintel - typo. You'd certainly get a steel to span 3m, under 250mm high, and I'm guessing an off-the-shelf steel would be cheaper than using bits of hacked-about rainforest
Are you sure all the load isn't being taken by the standard lintels, and the weird ones are just there to look nice?

Edited by andy43 on Thursday 16th September 23:14

[Busamav]

The more I have thought about this detail , the more doubts I have as to its buildability / suitability and it is nothing to do with me

Have you spoken with the poor sod who is charged with actually making this " detail " work ?

[mrmaggit]

I agree, I think there are some typos (if you like) in there that I'd want clarifying before I'd go much further.

[Grandad Gaz]

Busamav said:

Have you spoken with the poor sod who is charged with actually making this " detail " work ?

Yes, I've had a long discussion with myself about it

I think I'll email the archtitect and hope I get a reply. If not a visit to the building inspector might be in order. The reason for using wood (I imagine) is it also doubles up as a wall plate, something you can't do with steel.

Thanks again for the useful pointers.

[eps]

Grandad Gaz said:

Busamav said:

Have you spoken with the poor sod who is charged with actually making this " detail " work ?

Yes, I've had a long discussion with myself about it

I think I'll email the archtitect and hope I get a reply. If not a visit to the building inspector might be in order. The reason for using wood (I imagine) is it also doubles up as a wall plate, something you can't do with steel.

Thanks again for the useful pointers.

Just out of interest what would you do with a wall plate like that? Of course attaching something to it, will increase the load, possibly significantly.

[Grandad Gaz]

eps said:

Grandad Gaz said:

Busamav said:

Have you spoken with the poor sod who is charged with actually making this " detail " work ?

Yes, I've had a long discussion with myself about it

I think I'll email the archtitect and hope I get a reply. If not a visit to the building inspector might be in order. The reason for using wood (I imagine) is it also doubles up as a wall plate, something you can't do with steel.

Thanks again for the useful pointers.

Just out of interest what would you do with a wall plate like that? Of course attaching something to it, will increase the load, possibly significantly.

It's all to do with height. Due to restrictions, using it as a wall plate will reduce the overall height as compared to a metal lintel, where the wall plate would be bedded on. We are already down to 15 degrees and cannot afford to increase the depth of the lintel.

Is there really a metal lintel that would span a 3m opening and not more than 125mm deep?

What would you suggest?
Cheers

Just checked for the SB/K lintel to the outside leaf. It seems they only go up to 2700mm. Bit of a bugger as the opening is 3000mm!

btw, the spec for buildings regs is approved by an outside company and not the councils inspectors. No, I don't understand that one either!

Edited by Grandad Gaz on Friday 17th September 15:49

[Busamav]

It could be a designed piece of steelwork instead of a purchased lintel.

Maybe a small channel with a steel bottom plate welded on to carry the outside brickwork.

At the present , that detail shows the bricks as " floaters " , at that scale you really should not be letting drawings like that leave the office.