Replacing sheathing on a roof

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swimmer_spe

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I may be buying a house that needs a new roof. I am fine with the cost and the work needed to do it. I am good with tools.

My problem is the layout and condition of the roof.

Picture the roof: The house is rectangular, with a loft in the middle. The 2 outer roofs slope to the long ends of the rectangle, the middle, upper part, slops to the shorter ends of the rectangle. Confused yet?
The roof is a low sloping roof, likely 4:12

The upper roof is bowing. I can clearly see where the rafters are while standing on the ground.
I know I need to replace the entire roof. I know that where the bowing is, the sheathing must be replaced.

How the heck do I do it? I do not think I can access the attic and push the sheathing out.

I have time, and, given the damage, I have the money to do it myself.
http://www.realtor.ca/propertyDetails.aspx?PropertyId=14852046 First picture shows the layout of the roof, but not the damage.

Any help would be greatly appreciated.
 
Going to need some better pictures then that.
Is it the ridge beam that's sagging in the middle?
 
joecaption said:
Going to need some better pictures then that.
Is it the ridge beam that's sagging in the middle?
Click to expand...

Nope, just the sheathing. The beams and rafters look fine. It looks as though the last roof job was done without any care to the sheathing.
 
How good of a deal is the house compared to the market around it? Is it significantly low priced to cover the cost having it professionally replaced even if you DIY. Are there other major issues to factor in to the low pricing.

A project like this is a fairly big deal as a DIY and depending on equipment you have would make a big difference. If I was replacing that sheathing I would remove and replace as I went I think starting at the bottom and going up using the new as staging for the higher work. You may still need to set up or build some scaffolding to position yourself to do the work from the lower roofs. Doing the project this way you would have less open to the weather as you go along.

A pro would have a much different approach as he would blow thru the job in a day or two.
 
bud16415 said:
How good of a deal is the house compared to the market around it? Is it significantly low priced to cover the cost having it professionally replaced even if you DIY. Are there other major issues to factor in to the low pricing.

A project like this is a fairly big deal as a DIY and depending on equipment you have would make a big difference. If I was replacing that sheathing I would remove and replace as I went I think starting at the bottom and going up using the new as staging for the higher work. You may still need to set up or build some scaffolding to position yourself to do the work from the lower roofs. Doing the project this way you would have less open to the weather as you go along.

A pro would have a much different approach as he would blow thru the job in a day or two.
Click to expand...


If the roof and the other work I am going to do were done, the house would easily sell for $150k. I am getting it for under $50k.

Can you put scaffolding on the lower roof? How?
 
You would have to protect the lower roof from damage first with some padding. And something to spread out the load. Plywood maybe. You could frame up some sort of support to work off of that would sit and straddle the ridge of the lower roof. Again a pro would have the equipment but the DIYer would have to rent or improvise. Renting equipment for a short time period is a great deal but renting for a long time period can soon get you to the point of buying it.

Sounds like you have a lot of upside potential with your house and as long as the numbers look good and you can do the work then I would go for it.
 
How old is the house? If it is less than 35 years old the roof sheathing is very likely 7/16" OSB. If the joists are 24" OC (more common with trusses) the OSB will tend to dip between joists. Plywood doesn't do this as much. Structurally the OSB is fine but it does look bad. Using an architectural shingle will do a better job of disguising the waves on the new roof. Using plywood or thicker OSB will reduce/eliminate the wave.
 
bud16415 said:
You would have to protect the lower roof from damage first with some padding. And something to spread out the load. Plywood maybe. You could frame up some sort of support to work off of that would sit and straddle the ridge of the lower roof. Again a pro would have the equipment but the DIYer would have to rent or improvise. Renting equipment for a short time period is a great deal but renting for a long time period can soon get you to the point of buying it.

Sounds like you have a lot of upside potential with your house and as long as the numbers look good and you can do the work then I would go for it.
Click to expand...

I am replacing the entire roof, so, as long as I do not damage the sheathing, if it is still good, on the lower roof, I am not overly concerned about the shingles. I plan on doing the upper part first, then the lower parts.

I figure I should be able to do it in a week or less. Locally, weekly rentals are cheap.
 
Sparky617 said:
How old is the house? If it is less than 35 years old the roof sheathing is very likely 7/16" OSB. If the joists are 24" OC (more common with trusses) the OSB will tend to dip between joists. Plywood doesn't do this as much. Structurally the OSB is fine but it does look bad. Using an architectural shingle will do a better job of disguising the waves on the new roof. Using plywood or thicker OSB will reduce/eliminate the wave.
Click to expand...

House is from 1955. Garage is from 1995, and it looks like the roofs of both are the same.
 
swimmer_spe said:
Ok, but how do I get on it and be safe? I think that the sheathing has lost all strength and am worried that I will fall through.
Click to expand...

The only reason you would fall thru is rot or a lot of water damage likely not enough venting, rafter too would be in bad shape, reomove some drywall and and inspect from below.. Built in the fifties, I would expect to find 3/4" shiplap.
 
nealtw said:
The only reason you would fall thru is rot or a lot of water damage likely not enough venting, rafter too would be in bad shape, reomove some drywall and and inspect from below.. Built in the fifties, I would expect to find 3/4" shiplap.
Click to expand...


Built in the 50's likely plaster and plaster board, not drywall. Roof could be plywood or T&G as Neal mentions. My dad built my childhood home in 1954 and there wasn't any plywood in it, roof sheathing and sub floor was T&G.
 
Sparky617 said:
Built in the 50's likely plaster and plaster board, not drywall. Roof could be plywood or T&G as Neal mentions. My dad built my childhood home in 1954 and there wasn't any plywood in it, roof sheathing and sub floor was T&G.
Click to expand...

If the sheeting is rotten, the rafters are rotten , plaster is gone anyway.
Second floor loft may be an addition, anything may be found, but most often not enough venting. Better safe than sorry, cut some holes in the ceiling and see what you have.
 
If the house is a fixer-upper, you will have plenty to keep you busy. You may want to save your strength - and time - for the projects you are familiar with. Get a couple of bids from the pros, see what they have to say, and then decide if the roof is DIY.
 
You haven't bought the house yet, so cutting holes in the ceiling isn't an option, I would think. There must be access to the attic someplace in the house, so get up there next visit. If the loft doesn't have it's own access from the living space, it may have an opening from the attic.
 
slownsteady said:
You haven't bought the house yet, so cutting holes in the ceiling isn't an option, I would think. There must be access to the attic someplace in the house, so get up there next visit. If the loft doesn't have it's own access from the living space, it may have an opening from the attic.
Click to expand...

I did see a small access door on the other side that would allow me access to the underside of the roof. Tomorrow is when the Home inspector does his inspection. I will ask him to open it to look in.

If nothing is black or wet, why would the roof sag like that?
 
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