Timber framed carport/garage

Phaedrudge · Post by **Phaedrudge** » Thu Jun 24, 2021 11:21 am

Hi,
I'm planning to build a 10m x 3m freestanding carport and garage roof cover along the lines of the attached pics.
Posts and beams in 5" x 5" pressure treated
Posts 2.4m height at 2.4m between centres
Pitched roof to 1m at ~34 degrees
Rafters in 6" x 2" C16 using ridge board and bird mouth joints
Roof in box profile poly coated steel 1m width * 2m length
2.5" braces between posts and beams
Steel concealed (filch plate) post bases (CPT66Z) bolted to concrete.

Some questions:
Will the post bases be sturdy enough for the loads or should I concrete the posts in?
Do I need joists across the rafters?
Anything else I should consider?

Thanks for any input.

moderator2 · Post by **moderator2** » Thu Jun 24, 2021 11:24 am

Moved to Carpentry

Phaedrudge · Post by **Phaedrudge** » Thu Jun 24, 2021 11:40 am

Thanks - given the post setting requirements - is Carpentry the right place?

ayjay · Post by **ayjay** » Thu Jun 24, 2021 2:04 pm

The post supports will be OK. The biggest problem with them is cutting the slots, a chain saw is the best tool for that, but it can be done the long-winded way with a hand saw, drill and chisels. Make a template (and test it) for drilling the dowels.

Any standard pitched roof needs tying in across the bottom of the rafters, the weight of the roof will always create outward thrust at this point.

Phaedrudge · Post by **Phaedrudge** » Thu Jun 24, 2021 2:42 pm

Thanks for putting my mind at ease on the posts.

Circular saw or table saw to cut the slot?

To be fair, hiring a chain saw to cut the slots is a good option as it will get the job done quickly first time and square at the end...

aeromech3 · Post by **aeromech3** » Thu Jun 24, 2021 4:35 pm

With ayjay, a Titan chainsaw from S.fix £50 will also serve you for the other cuts; it will give you minimum 5mm width slot where a circular saw will be 3mm and not flat bottom, cutting with the grain always easy to wander off.. Using CPT66Z you need to be accurate with the dowel holes or posts won't be vertical, almost worth making a jig support or at least a long square and spirit level.

Neelix · Post by **Neelix** » Thu Jun 24, 2021 4:55 pm

Dare I suggest do you need planning permission?

oz0707 · Post by **oz0707** » Thu Jun 24, 2021 7:17 pm

I'd price it up in some kind of hardwood treated if you can? Honestly pressure treated timber isn't worth a wan... nowadays. At least hardwood for the exposed sections anyway.

Its like the price difference between softwood and oak sleepers. Its not as big as you think especially when it could last 50 years as opposed to 10

oz0707 · Post by **oz0707** » Thu Jun 24, 2021 7:20 pm

I wouldn't conc posts in, do as you say with the brackets.

Prob need some 3x2 on flat across top of rafters you will be able to confirm with manufacturers spec for the covering

Phaedrudge · Post by **Phaedrudge** » Mon Jul 05, 2021 10:22 am

Neelix wrote: ↑Thu Jun 24, 2021 4:55 pm Dare I suggest do you need planning permission?

As the extended size of the garage is only about 20 sq.m, I don't believe so. Checked with the neighbours of course and they are fine with it.

Phaedrudge · Post by **Phaedrudge** » Mon Jul 05, 2021 10:26 am

oz0707 wrote: ↑Thu Jun 24, 2021 7:17 pm I'd price it up in some kind of hardwood treated if you can? Honestly pressure treated timber isn't worth a wan... nowadays. At least hardwood for the exposed sections anyway.

Its like the price difference between softwood and oak sleepers. Its not as big as you think especially when it could last 50 years as opposed to 10

I know what you're saying, I wanted oak, but the price difference on all hardwood is massive (at least double) - it's also that much harder and heavy for me to work on my own (obviously this is good for structure, bad for my back).
We'll only be here for 15 years max, so I'm happy with the timber as is...

Thanks for the input though.

Nos · Post by **Nos** » Tue Jul 06, 2021 7:03 am

If you still have libraries in the Uk I suggest you read this book " Learn to Timber Frame" by Will Beemer, although its an American publication it has a lot of excellent information and guides and photos, for a project such as yours, I got mine off Amazon, just checked todays price £14.49.

Phaedrudge · Post by **Phaedrudge** » Wed Oct 20, 2021 8:52 am

Hi all,
frame is up and I'm onto the roof... In the original design I described a ridge board... Now looking at the best options.

Roof pitch 3:12.
The rafters are actually C24 with a clear span of 1.75m.
I'm looking at using an overlap joint on the rafters at the ridge,
Looking online, a ridge beam is the best way to go.
Supported by 5" x 5" posts on the cross beams at ~2.5m spacing...

Any suggestions on the size of the ridge beam?

Cheers.