Fitting fascia to pent roof rafters

[porridgebear]

Hi,

I've been building a garden shed (spec. similar to a garden roof however) and this weekend the 6x2 rafters went up onto the header plates with bird mouths and inverted joist straps.

At the moment I have not faced the rafters back and front with a single length board, thereby creating a squared frame, i.e. I fit the first rafter and used 2 24" spacers to gradually work my way down to the other side.

Fitting a front/back face was my next step but at 4m long these 6x2 boards are HEAVY and I wondered whether they are necessary.

I get that they would firm up the frame. But I could also introduce noggins along the top plate at front and back to provide similar rigidity.

Instead, I was thinking of fitting a thicker fascia board directly to the rafters at front/back which is uPVC so much lighter.

My questions are:

1. Do I need to use these heavy 6x2s (that I used for the rafters themselves) to face them at front and back? Is their function mainly for attachment of a fascia or squaring of the roof?
2. Could I get away with not using them and fitting a thicker 19mm fascia direct to the rafters, or would issues occur over time because of the underlying movement of rafters
3. If I should really use wood first before fascia, will it be ok with the 6x2 or do others use a thinner wood 6x1 or something?

Thank you!

 

[Adam W.]

Brace the walls instead and plumb the ends of the rafters, then screw a 1" fascia straight on.

 

[porridgebear]

Thanks, OK interesting.

Here is a photo where things are now if useful. Walls are all plumbed and supported with noggins. I was thinking 4x2 noggins in between each rafter front and back on the top plates might be handy for providing extra rafter rigidity, then just fascia direct on

This is the type:

https://www.directplastics.com/upvc...d-fascia-boards/anthracite-grey-square-fascia

 

[Adam W.]

The ply you screw on the roof will make it stiff, but you've got no bracing in the walls to stop it wracking.

 

[porridgebear]

Thanks Adam - hm - I must have watched 20+ garden building/shed builds on YouTube and I've not seen anyone doing any kind of wall bracing beyond the noggins, the structures follow what I've put in the photo above.

1. Are you saying the omission of front/back 6x2s on the roof rafters is what leads to needing bracing?
2. or are you saying bracing is needed regardless of what I do with the fascias to the rafters?
3. What kind of bracing are you referring to - metal straps, diagonal wood lengths, something else?

Sorry if obvious, I'm new to all this but def. not seen anyone doing bracing - winds mostly light and it's in a corner of the garden against a fence.

Thanks for the advice!

 

[Adam W.]

It's OK, I'm happy you're asking.

The roof will be fine with ply and a 1" faschia. Ditch the 2x6, but you can put some noggins in to close up the gaps at the front and back edges if you're not going to mount a soffit.

The walls need bracing with either diagonal timber braces in between the studs or by screwing ply to the studwork on the inside or the outside.

 

[porridgebear]

OK phew - yes I have 12mm ply for internal walls and 9mm ply for the ceiling and 12mm ply for roof (on which will be EPDM).

Going straight on with fascia sounds great. I do plan on using vented soffit board at front and back. I might just pop some noggins between the rafters like the stud walls but perhaps not every rafter.

Thank a lot, appreciate the help on a Sunday

 

[Fergie 307]

I would certainly put noggins between the rafters in the centre at least, otherwise there is nothing to prevent them wracking over. Personally I would put them in over the top plate as well on every other one.