shed build - gable ladder advice

[amh82]

Hi guys, I'm new to this site, but whilst reading around for inspiration in workshop/shed builds I often found lots of great builds on here - so thought I'd join up!

I am in the process of building a shed/summerhouse, I am now at the point of building the roof and have a few questions!

Short version, the shed is 3.6m x 3.0m, apex roof with gable across the long edge. Floor is 4x2 with 18mm ply, walls are 3x2 and the a frame trusses are 4x2 rafters, 3x2 bottom chord & 18mm ply gussets, 17.5' pitch. I'd add some photos but on my phone at the mo!!

I would like to extend the gable and had looked at various metods and decided on using gable ladders.

Like this:

Could someone advise what the max advisable overhang should be? 400mm? The roof will be over boarded with 18mm ply, then most likely underlay & felt shingles.

Is there anything I should do to prevent sagging? Bolt rather than screw to gable truss? Any need for strapping across the top, or even gallow brackets? Noggins from gable truss to first truss to better support cantilever?

Other  question I have, the framework is unclad at the mo, but covered with breathable membrane. Should I clad the gable truss before fitting the gable ladders, or does it make no difference whether cladding is sandwiched or not?

I was planning on fitting the cladding after the gable ladders in case I want to remove it in the future without disturbing the roof (shrinkage/damage).

Here is the build as it stands...

2016-05-11_11-07-00 by Hallsy01, on Flickr

2016-05-11_11-06-09 by Hallsy01, on Flickr

Well...actually, it's now covered in membrane thanks to our variable British weather - nice & sunny today though!!

Any advice much appreciated

 

[amh82]

Hopefully I've added a couple of photos to show the build. - actually no, the site won't let me add links to photos yet, guess that's because I'm new?

The total rafter length is around 1970mm iirc, so span is around 1800, a touch longer I'd say without measuring.

I had planned to nog the gable to first truss at 16" centres, same as the ladders, thinking that that will also help support the cantilever.

I have had a suggestion that it would be wise to use gallows brackets at the midpoint to help support the span and also resist sagging.

If I went with gallows brackets midpoint, should I birdsmouth the rafters to suit, or place them under a noggin that is set plumb (so bearing face square to gallow bracket) rather than square to rafter?

Shame I can't add photos as they would be better than my descriptions!!

 

[amh82]

Ah....I have just found the rules page and can see I need to make three posts before I can add links.

That clears that up!!

 

[MMUK]

Would have been much easier with extended ridge and eaves beams.......

 

[RobinBHM]

maybe do an extra thick fascia, say 4 x 2 or 5 x 2 and run this on to give the extended part some strength.

Or add a ridge on top of your roof and so the same thing -it will just need dressing over with lead or felt which could add a nice detail.

The key is support at the bottom, it is likely to sag. I suppose gallows brackets would do, but might look a bit awkward

 

[hanser]

Hi

I'd bolt the ladder on, screw galvanised straps onto the ladder and then fix back over the frame truss and next truss. Finally fashion and fix some eaves brackets - a little less clunky than gallows brackets.