Hi guys,

I'm going to be re-sheathing and re-shingling my shed. Its 20x20 and has a low pitch flat roof. I have a few questions:

Do I need Ice/Water shield at the soffit? The shed isn't heated and it is not attached to the house. Will plain old felt work just fine instead?

Also, the rafters are 24" O.C. What is the minimum thickness OSB should I use? Thanks!

 

IMO at least 1 row of ice and water shield would still be a good idea. On days when it gets warm enough to melt, icicles will still form on the roof edges from the heat of the sun, and this could eventually end up being an ice dam. If you want to be sure it doesn't leak when the sun comes out in the spring and melts all the snow that's standing on the roof, then apply ice and water shield to the whole roof since it is "low slope".

You didn't say how low of a slope it is, but if it is 2:12, your rows of felt paper should be lapped at least 12" in lieu of ice and water shield so as to provide additional protection for the roof sheathing. (minimum of 5/8" thick) If it is 3:12 overlap felt paper at least 6".

 

Don't have time to go out and take a measurement of the slope (Bruins are on) but here is a pic from the kitchen.

 

It looks to be less than 2:12, perhaps 1.75:12, if my tri-ruler is correct. Never measured a roof on my computer before... LOL! And that sag in the roof doesn't help matters... if there is a dip in the middle, the pitch could be even less in some areas.

Asphalt shingles aren't recommended for such a low slope. Have you thought about a steel roof?

 

No I havn't thought of a steel roof....but that certaintly is an option. This shed was originally a horse/carriage barn and has stood for 110 years. I'm not sure what type of roofing material was but there are two layers of asphalt shingles on there now and the original pine planks have finally rotted out. At the very least I'll be resheathing it. As far as what type of roofing material I go with...I guess that is still up in the air and open to suggestions.

I only have two concerns....it has to look halfway descent and I don't want to spend alot of money. What are your ideas?

 

There are various kinds of metal sheet roofing, from galvanized to any color you like, white, red, green, etc. Metal roofing costs more, but depending on what style you went with, you could get it ordered in sheets that are just as long as your roof is, and they are usually 3' wide. So for a 21' long roof, you'd only need 7 sheets.

You would not need to sheet the roof... you could go over it with 2x4 perlins laid flat, attached perpendicular to your rafters every 32" or so. (or tear off existing sheathing so that you can better attach the 2x4 perlins) You'd also want a solid perimeter of 2x4 flat around the edges. Gable closure would cover the top and ends. Drip edge would be installed along the bottom edge before applying the 1st sheet.

Metal roofs look best when the framing is perfectly straight so if you can beef up your old sagging rafters with some gussets it would probably give the roof a real face lift.

 

That sounds real nice! I'll definetely have to explore that route. Where is a good place to look for these metal products?

 

Big box stores might be the most economical. But if you have any farm stores nearby they could also order it for you. (all metal is usually special order, when you want a specific length that isn't a standard size). You'll measure your exact roof length and width (not the walls, obviously) and factor in a little extra overhang on the bottom edge, like 2" or so. If you take them a drawing or picture of the building they can get you all the parts you need. You will probably need them to deliver it too, since 21' is too long for a pickup. Because of that, your local lumberyard would probably be a good place to start!

You can also get an idea of what buildings look like with metal roofs, go to google, click on images, and type in metal roofs or steel roofs or metal roofing.