Loft conversion ridge beam support help

[JohnnyS]

Hi all,

just after a bit of advice on a 1930s 3 bed semi, dormer loft conversion.
The drawings for the steels include a support for the ridge beam to run up against the chimney breast between the ridge beam and a new beam below it.
The chimney breast has already been removed at the lower levels so all that remains is the stack and the breast in the loft, currently supported by steel beams running from the front to rear wall.

The builder has said that he does not believe the support for the ridge beam is required as it wont be doing much and it's worth him discussing it with building control to give us the extra space if not needed.

I just wondered if the ridge beam support is a common feature in loft conversions? I believe its job is to take some of the load off the chimney breast.

Any advice on this is appreciated,

Thanks
John

 

[^woody^]

Surely the ridge beam is supported at each end, so what's that post doing?

If the post is supporting one end of the ridge beam than how can the builder even suggest that the post is not doing much?

Presumably ridge beams and posts and stuff have been designed by a structural engineer and are not up for discussion for removal by a builder.

 

[tony1851]

If a chimney stack comes up through the ridge, it is normal to support the ridge beam off a post. In your case, it seems the post is supported by a beam at loft floor level.
If there is a reasonable height of chimney brickwork below the ridge, it is often possible to support the ridge off a short post about 1m long bolted to the face
of the brickwork. This post can be a length of channel, or box section with lugs welded on for bolting. This saves the expense of fitting a beam at loft floor level. It is important that the fixing bolts don't go nearer than 50mm to the flue face, and that the brickwork is in reasonable condition.
What you should not do is listen to your builders' advice about not installing a post; the ridge carries part of your flat dormer roof and part of the front roof
and is a major structural element.

 

[JohnnyS]

Surely the ridge beam is supported at each end, so what's that post doing?

If the post is supporting one end of the ridge beam than how can the builder even suggest that the post is not doing much?

Presumably ridge beams and posts and stuff have been designed by a structural engineer and are not up for discussion for removal by a builder.

Thanks for the reply. The ridge beam will run wall to wall but and also (i believe) through the chimney at one end so the load will be spread. Due to the load being spread on the party wall and chimney at one end the builders feel the use of the ridge support on that side againts the chimney breast will be of little use, he seems to have some knowledge on steel and load bearing.

Thanks

 

[tony1851]

The wall within the chimney itself will likely only be one-half brick thick (is this a joint chimney with next doors'?)
If the chimney is on the party wall, inserting a padstone will cause muck to fall down the neighbours' flue.
But your builder seems to know all about 'steel and load-bearing' so take his advice and ignore your SE.

 

[JohnnyS]

The wall within the chimney itself will likely only be one-half brick thick (is this a joint chimney with next doors'?)
If the chimney is on the party wall, inserting a padstone will cause muck to fall down the neighbours' flue.
But your builder seems to know all about 'steel and load-bearing' so take his advice and ignore your SE.

I dont think i fully grasp the way the ridge beam will sit in relation to the chimney so my explanation might be wrong. Thank you for the replies and your time.

Thanks
John

 

[^woody^]

builder seems to know all about 'steel and load-bearing' so take his advice and ignore your SE.

Is that to the OP or the BCO?

Will the builder certify his design and have insurance cover for the future years in case everything starts moving?

 

[Ian H]

Tony is on about something like this:

As I understand it, you can’t knock into the chimney to support directly off it.

 

[^woody^]

Tony is on about something like this:

As I understand it, you can’t knock into the chimney to support directly off it.

That's a nonsense concept.

Can't bear a beam into the breast, but can fix a massive box section bolted to the very same wall in six places but doing nothing half way up the wall, and then with a skinny 4x2 timber below that?

Who comes up with this crap?

 

[Ian H]

That's a nonsense concept.

Can't bear a beam into the breast, but can fix a massive box section bolted to the very same wall in six places but doing nothing half way up the wall, and then with a skinny 4x2 timber below that?

Who comes up with this crap?

Someone that knows the inside of chimneys get hot? Someone qualified?

The timber doesn’t stay there.

And the original 6x1 ridge board didn’t go into the chimney either

 

[^woody^]

Someone that knows the inside of chimneys get hot? Someone qualified?

Oh I see, someone that designs for the picture not yet posted and not for what's in the picture originally posted. Please excuse my telepathy skills which have been below par of late.

 

[tony1851]

That's a nonsense concept.


Who comes up with this crap?

If the chimney is in use, then it is not permissible to run a steel beam into it. Fixing a steel post to the brickwork face to support the end of the ridge beam is perfectly acceptable. The proviso is that no metal fixing must penetrate nearer than 50mm to the inside of the flue, which suggests bolts no longer than about 75mm. As long as the bolts are reasonably spread out, and into whole bricks, then there is no problem.
This is a common method of supporting a steel ridge beam off a central chimney in a party wall; would have thought that most surveyors would understand that?

 

[Ian H]

Oh I see, someone that designs for the picture not yet posted and not for what's in the picture originally posted. Please excuse my telepathy skills which have been below par of late.

Someone’s been and designed it haven’t they? And the builder disagrees, maybe he’s right if the chimneys have been removed, maybe not.

I’ll excuse you this once but please brush up on your telepathy.

 

[JohnnyS]

Hi all,

I really appreciate all the detailed info and pictures, thank you.

The remaining chimney is not in use (supported in the loft with actual steel beams at or just below current floor level), im not sure if that makes any difference to it partly taking the load from the ridge beam. It does sound like the support column is the safe option, but it will still be interesting to hear building controls comments on it.

Thanks for your help so far.

John

 

[tony1851]

it will still be interesting to hear building controls comments on it.

In all probability, building control will just say do what the SE has designed.
When you think about it, why should an inspector take it upon himself to suggest an alternative, when you consider who
would then be liable if it failed? - the SE would disclaim any responsibility.