Lean to roof

[dim4762]

Hi

Wonder if somebody could help. I have recently knocked down a very old lean-to shed. I am attempting to rebuild it but slightly larger. I am going to use the original imperial size bricks. I have laid the footings and will soon start the brickwork. This will be the first time I have built anything but am looking forward to the challenge. I did attend a bricklaying course some years ago!

I should explain that I will be building off an existing wall (which I have raised to get the pitch). My main worry, is when I get to wall plate. I can think of many questions to ask but would be here all night. Firstly, what size wall plate will I need. Do I just need rafters up to a wall plate/ridge board (what size rafters and wall plate/ridge board). As the wall is only single skin, I was going to rest the wall plate and ridge board onto the wall (straps and bolts also) and use the exposed ends of wood to nail fascia to. Again never done any kind of rafter cutting but google is a wonderful thing (suggest any sites). Also would I need to put joists across to existing wall (I wasn't planning on doing as original roof didn't). Shed size is 3.0m x 1.7m. Tiles will be original clay pantiles.

Many thanks for looking and I know I will be on again.

 

[noseall]

us a 100x75mm tanalised wall plate.

you may get away with 100x50mm rafters at 400c/c., if not, i'm sure 125x50mm will eat it.

use a 125x50mm pitching plate (high end) either below the rafter ends or at the rafter ends, bolt this to the wall every other rafter gap, staggering the bolts.

you can leave the rafter ends long then trim them to a suitable soffit size using a string or straight-edge guide. measure off the external masonry to each end rafter then run the straight edge or string to these marks.

the rafter ends will be cut at the same pitch throughout, use a level (set vertical or plumb) if you wish - this will provide you with the bevel angle.

the fascia will be nailed directly into the rafter ends.

you can fit cradling to the rafter ends to support the soffit.

don't forget ventilation.

 

[dim4762]

Thank you Noseall for the invaluable information. I will do as you suggest. Any tips on cutting rafters, I have never done this before but have looked at many websites. I presume once I build to top of door level, I know the wall plate obviously goes on next. Then do I fit the pitching plate and rafters and then brick up the two sides of the shed to the rafter pitch or the other way round, ie brick up first then rafters/pitching plate.

I hadn't thought of ventilation. As I'm using original clay pantiles surely the air will flow through the front of the roof between the "s" shape of the tiles where the fascia meets the overhanging tile?

Also I wasn't going to bother with soffit, I was going to put the fascia tight to the brickwork. Not sure if this is OK or not. Personal preference I presume?

 

[noseall]

you will bed the wall plate first, decide on the pitch and set the pitching plate once you have cut the first rafter.

for plain tiles you will require a pitch no less than 35 degrees. i have a chop saw with a gauge, so i just set it to 35 deg.

you can buy a simple angle finder, pop it on top of the rafter and raise it until it reads 35 degrees, then draw an upright line on the rafter and you will have the angle of cut.

you will need to cut a birdsmouth onto the wall plate. the vertical element of the birdsmouth is the same as the rafter ends and the horizontal element will be - er, horizontal or bubble level.

once you have fixed all the rafters and joists you then build the gable masonry to suit the rafter pitch. don't forget to fix any noggings to the end rafters should you wish to fit barge board.

there is nowt wrong with having no soffit but it can look odd particularly if the main dwelling has a soffit. overfascia vents can be used in this instance or just use breathable membrane to vent the roof.

i think a lean to roof looks well by stopping the fascia and soffit at a corbelled overhang thus doing away with any barge boards.

 

[dim4762]

Thank you noseall for all your thoughts. I will post back as I build. Your expertise has been invaluable. I have read your other posts in this section, you are certainly very popular. Thank you once again.

 

[dim4762]

Hi all,

Has taken quite a while but thanks to much advice from this forum, the shed is almost complete. Just lead flashing and a door to hang plus lighting.

Just when I thought I could have a rest, now she wants a patio!!!!!

Many thanks especially Mr Noseall.

Untitled

• dim4762
• 29 Aug 2008
• 1

Untitled

• dim4762
• 29 Aug 2008
• 1

Untitled

• dim4762
• 29 Aug 2008
• 1

Untitled

• dim4762
• 29 Aug 2008
• 1

Untitled

• dim4762
• 29 Aug 2008
• 1

Untitled

• dim4762
• 29 Aug 2008
• 1

Untitled

• dim4762
• 29 Aug 2008
• 1

Untitled

• dim4762
• 29 Aug 2008
• 1

Untitled

• dim4762
• 29 Aug 2008
• 2

Untitled

• dim4762
• 29 Aug 2008
• 1

 

[JohnD]

Just when I thought I could have a rest, now she wants a patio!!!!!

If she is that tiresome, excavate quite deep for the patio.

 

[dim4762]

Now that is something worth thinking about!!!!!!!!

 

[noseall]

top job!

effin brill.

wanna job?

 

[Deluks]

top job!

...and not a 'bricky' tool in sight!