3m concrete lintel 100mm x 65mm

[Ttw]

I have an opening of 2500mm and need to ideally use a 100mmx65 concrete lintel. 

 

My concern is will it be OK if my roof joist sit directly on the lintel at 400mm centres. The length of the joists are 3300mm. 

 

Any advice will be appreciated 

[Declan52]

You need to build over it to give it is strength.

Your roof will be very low as head height is 2.1m which will mean your ceiling is 2165mm which will feel like a cave.

[Ttw]

2 minutes ago, Declan52 said:

You need to build over it to give it is strength.

Your roof will be very low as head height is 2.1m which will mean your ceiling is 2165mm which will feel like a cave.

Its for a garden room and needs to be 2500mm under the permitted development ruling.... I should've gone for doors less than 2100 high that would've allowed for more options for a lintel. The doors were pretty much half price though and I'm a sucker for a bargain 

[Declan52]

So what is the roof build up??

3.3m you could double up 6*2 for joists.

[Russell griffiths]

I would look at planning permission and build it properly. 

 

That lintel will bend like a boomerang and your doors won’t open. 

 

You need to do it differently. 

Two kerto timber beams over doors with maybe a steel flitch plate between them, then hang your roof timbers from the inner face of the timbers NOT on top, this will keep your height down. 

 

Theres a million ways to do it, but that skinny concrete lintel is not one of them. 

 

2150 is the lowest I would go with finish ceiling height. My ceiling in the place we live now is 2150 and it’s not exactly fancy and I’m only 5 foot 6. 

[Ttw]

15 minutes ago, Russell griffiths said:

I would look at planning permission and build it properly. 

 

That lintel will bend like a boomerang and your doors won’t open. 

 

You need to do it differently. 

Two kerto timber beams over doors with maybe a steel flitch plate between them, then hang your roof timbers from the inner face of the timbers NOT on top, this will keep your height down. 

 

Theres a million ways to do it, but that skinny concrete lintel is not one of them. 

 

2150 is the lowest I would go with finish ceiling height. My ceiling in the place we live now is 2150 and it’s not exactly fancy and I’m only 5 foot 6. 

Unfortunately I couldn't wait for the 8-12 weeks planning application time. 

 

The roof is as follows however I can change for a better idea. 

 

C24 47x145 joists, 

Vapour barrier, 

18mm osb

100mm insulation 

11mm osb

Rubber roof finish 

 

If you could throw as many ideas that would suit carrying the flat roof joists but keeping the depth to around 70mm......id be absolutely massively grateful 

[PeterW]

Min spec to span that with flat roof load is a 100x215 concrete Naylor Lintel

 

I would use a pair of 8x2 C24 with a 150x8mm steel flitch plate across the opening between them bolted at 400 centres.

 

Hang your Joists off this, and you will get best of both worlds

[Russell griffiths]

20 minutes ago, PeterW said:

Min spec to span that with flat roof load is a 100x215 concrete Naylor Lintel

 

I would use a pair of 8x2 C24 with a 150x8mm steel flitch plate across the opening between them bolted at 400 centres.

 

Hang your Joists off this, and you will get best of both worlds

Is there an echo in here. ??

[PeterW]

Yep @Russell griffiths I've just seen !

[Russell griffiths]

Just now, PeterW said:

Yep @Russell griffiths I've just seen !

Good minds think alike ??

[Russell griffiths]

It all comes down to the design of the rest of the building really. 

 

Why the warm roof ?? They eat up height. 

 

Do you have a drawing of it. Or just winging it as you go along. 

If so you need to do some sketches or you will end up in a world of pain.