Raising Garage Ceiling - Is this possible?

[Harrier23]

Hi,

Looking to see of this is possible in theory before getting too ahead of myself with ideas.

I have a single storey detached garage with an 8' 4" ceiling which I need to raise up in a small section.
I think I would need to remove about 3 of the ceiling joists to give me the overhead clearing I need in the centre of the garage.

Has anyone done something similar and I theory would the bottom structure in the attached image work? The top structure is what I currently have and is what would remain in place for all other joists.

Read more: https://www.diynot.com/diy/threads/raising-ceiling-is-this-possible.561247/#ixzz6j5G9UnPM

 

[23vc]

You can’t just modify trusses (which is what your top pic is of), as they’re purpose built structural elements. If you take a chunk out of the bottom horizontal (ceiling tie) it’s likely the roof will spread/collapse.

you might need to introduce chunky timbers/purlins/steels for what you’re trying to do. Normally go to a structural engineer to get something designed. Or if you’re lucky there’s one around here sometimes...

 

[Harrier23]

Thanks. I have since seen this so might look into whether it would be feasible as the roof structure seems to be similar, just on a bigger scale.

 

[Harry Bloomfield]

Has anyone done something similar and I theory would the bottom structure in the attached image work? The top structure is what I currently have and is what would remain in place for all other joists.

The House of Commons (I think I have seen it), uses that very same basic structure style, but it was designed and built like that from scratch.

 

[endecotp]

The House of Commons (I think I have seen it), uses that very same basic structure style, but it was designed and built like that from scratch.

https://en.wikipedia.org/wiki/Hammerbeam_roof

(You might be thinking of Westminster Hall, not the house of commons.)

I imagine something simpler would suffice in this case.

 

[Harrier23]

Any idea of an approximate cost for SE advice on this?

 

[Harry Bloomfield]

https://en.wikipedia.org/wiki/Hammerbeam_roof

(You might be thinking of Westminster Hall, not the house of commons.)

I imagine something simpler would suffice in this case.

Yes, you are right! And no need for the elaborate carving and gilding

 

[23vc]

Any idea of an approximate cost for SE advice on this?

Maybe 200-400. But seeing as it’s a detached garage, you can basically do what you like, you haven’t got building control requiring calcs. Might be worth seeing if anyone else here comes along who has done similar, or researching online for possible solutions before shelling out.

 

[^woody^]

2-3 trusses in the centre of a roof is unlikely to be an issue, as long as it's all braced (chevron braced) afterwards.

It's not clear what you are trying to achieve, but generally ...

Use timber sections from standard cut roof tables to double up the top chord before removing the webs and bottom chord. Then again use sections from tables for the collar tie. It might need a central hanger to support the collar. Then make good the bracing to tie the whole roof together.

Ad-hoc webs might be an alternative if you just want to recreate raised collar trusses - is just copy the trusses for the webs, but with a raised bottom chord.

 

[Harrier23]

Sorry, I could have been a bit more specific with what I am needing it for. I will need about 1-2ft of additional clearing to allow me to install a golf simulator, basically enough to swing a club without putting a hole in the ceiling. The opening would be central widthways but not necessarily bang on centre lengthways, but not far from it.

Ad-hoc webs might be an alternative if you just want to recreate raised collar trusses - is just copy the trusses for the webs, but with a raised bottom chord.

I have seen a similar topic on this forum where someone suggested the attached diagram as a solution, which I think is similar to what you are saying here?

I have also included a picture of my garage so you can see the structure.

 

[^woody^]

That image is a bit dramatic. You don't have the height or span to require something that elaborate. Looks like a a case of just forming a raised collar.

 

[Harrier23]

Thanks.

Just to make sure I have understood this right, installing a collar tie in the upper 3rd of the roof and then attach new webs above them to replicate the previous truss system should allow the existing trusses and joists to be removed?
This would be repeated for the 3 or so joists I needed out of the way and the end result would be an increased ceiling height from wall to wall, rather than just in a narrow central section?

 

[^woody^]

Post a plan of what you want