80 Year old 12x24 detached garage roof repair question

Platonic Solid · Jul 3, 2017

This garage/shed is all wood construction built on dirt. No foundation. It’s in sad shape, but is still standing and I’d like to at least keep it usable without getting carried away. If I wanted to spend real money on it, I’d bring in a dumpster and replace the whole thing. (I’m saving my money for a 2 story 6 car garage (3-up/3-down) on another property).

(image linked to larger image)

My only goal is to keep water from leaking through the roof.

The original plan was to remove the roll roofing – put a layer of 1/2” plywood over existing boards to create a more even surface – install drip edge, felt, roll roofing. Roof pitch is 5/12.

Now I’m wondering if it wouldn’t be much easier to just install either asphalt or metal panels and skip the plywood layer all together.

I have no experience with the panel options. I don’t mind spending a few extra dollars if it makes installation go faster.

Guidance appreciated.

Stuart in MN · Jul 4, 2017

I'm assuming some of the existing roof sheathing boards are in bad shape? is it possible to just repair/replace the ones that need it and then put down shingles? You don't necessarily need to add plywood, that's what I had done with the roof on my 100 year old house and it's holding up well.

Platonic Solid · Jul 4, 2017

Yes, some of the existing sheathing boards are in bad shape. The rest are also almost an inch thick and hard as rock. Replacing the bad boards is the right way, but this is one of those scenarios where removing the bad boards will probably lead to rafter repair which will lead to wall and stud repair... This is a property I rent out (shed not included). I'm looking to get in and out quickly. So far I've removed the roll roofing from the nasty side pictured.

On second thought, I think I'll skip the plywood. Band-aid the bad spots and just put down roofing felt and roll roofing. If it only lasts 5 years, I'm good with that. Even the bad spots are strong enough to hold my weight. Just need to put something flat there.

I should mention that the shed is full of stuff, so doing a simple rafter repair becomes a major hassle. All work needs to be done from the exterior.

6768rogues · Jul 4, 2017

I would scrape the junk off it and put down another layer of rolled roofing. It will last about 10 years.

rburke65 · Jul 4, 2017

Metal roofing? If you take it down save that old siding!

kbs2244 · Jul 4, 2017

Strip down to wood.
Let it dry for a few days.

Then I would go with those plastic panels.
Fast to install and lighter then metal.

Platonic Solid · Jul 4, 2017

@ rburke65: What's the deal with this old lumber? It's not like it's pressure treated. The floor is made of massive pieces of 6x10 - again sitting on dirt. My problem is I already save everything. I'll see what the lumber looks like when I get to that point.

@6768rogues: Agreed. I could have just put some 1/4 plywood on the trouble spots right over the old roofing, but that's too late now. I'll probably just put another layer on the other side as there's no major issues there.

I found some 1/4" plywood in the shed, so that's what I used to cover the bad spots.

Here are pics of yesterdays progress (yeah, I take pics when I first get there. By the time 2:30 rolls around I'm all hot and sweaty as there is no more shade from the giant maple tree. Then I just want to get the heck out of there).

Cyberbear · Jul 5, 2017

If you only want to make the roof leak proof, and not worry about appearance, then do as you suggested and cover the old roof with ply and then choose your roofing materials. From personal experience I find that rolled roofing only lasts about ten years, and asphalt shingles will go 25 or 30 years for quality three tab types, all of this over quality tar paper. Use spiral galvanized nails to hold the ply in place and install a strong fascia board for roof edge support. Too many have failed at not paying proper attention to this detail. Some material suppliers rent out pneumatic nail guns for the DIY crowd.

kbs2244 · Jul 5, 2017

My concern about any kind of asphalt roofing is weight.
That does not look like the strongest framing around.
The plastic sheets are light and water proof.

theoldwizard1 · Jul 5, 2017

Platonic Solid said:
This garage/shed is all wood construction built on dirt. No foundation.

IMHO, ANY amount of money to fix the roof is a waste without doing something about the lack of foundation and the obviously now rotten wood in contact with the dirt. If it is only going to be there for a year or so, cover it with a blue plastic tarp.

If you want to see this thing last more than just a couple more years you don't need a full foundation but the is a lot you can do.

Jack up one side so that it is a couple inches off the ground. Brace the other sides so they don't move.
Cut off about 1-2' of the rotten studs along with the rotten bottom plate.
Lay down a PT 2x8 that is the complete length of that side. You could also use some double 5/4 PT deck boards that are shorter so you can splice the with at least a 1/3 overlap. Add/remove dirt to make this level. You could also use a couple of additional non-PT 2x8 on top of the PT 2x8 to cover the splice and to move the whole structure up from grade 4-6".
Cut 2x4 to go under each stud that you cut off. Nail 1by on both sides of the existing stud and to the new "extension" down to the new plate so that it can not "kickout".
Toe nail the built up stud to the plate
You should use hot dipped galvanized or stainless nails on PT wood.

Far from perfect, but with some extra bracing in the corner (AFTER you have made the walls plumb and square) it will likely stand for a long time.

theoldwizard1 · Jul 5, 2017

kbs2244 said:
My concern about any kind of asphalt roofing is weight.
That does not look like the strongest framing around.

YES ! I would take a close look at the rafters especially where there is a big dip in the roof. Jacking the rafter back to straight and then sistering on some new lumber would make me more comfortable walking on that deck.

Platonic Solid · Jul 6, 2017

@ theoldwizard1 - I couldn't agree with you more. If I had the time and wanted to preserve the character, I would follow your advice. Going by memory, the structure is built like a mini poll barn with 6x6 (or 8x8) studs every 8 ft. or so. The floor, which is not attached to the structure, is various width 6 inch thick giant tongue and grove. The garage door has an interesting counterweight pulley system.

The repair I'm doing will cost less than $200. I could purchase a prebuilt 12x24 garage and have it delivered for $5000.

6768rogues · Jul 6, 2017

kbs2244 said:
My concern about any kind of asphalt roofing is weight.
That does not look like the strongest framing around.
The plastic sheets are light and water proof.

Asphalt shingle roofing is light weight roofing, at only 2 to 3 lbs. per square foot. Roll roofing is considerably less.

kbs2244 · Jul 6, 2017

A 26 x 72 sheet, covering 12 SF weighs 3 LBS
http://www.homedepot.com/p/Suntuf-2..._8903vry57826_pcrid_74285768029022_pkw__pmt__

Platonic Solid · Jul 6, 2017

@ kbs2244 - That's what I was considering, but was seeking real world experience/advice on using those types of panels. I'd have to use the 8ft version and from my calculations the materials to cover the whole roof (including ridge caps, closure strips and fasteners) = $900. At that price range I'd be smarter to cut my losses, tear the whole thing down and buy a new one.

SALIV8 · Jul 6, 2017

I'd price out layering some self adhering grace ice and water shield or galvanized panels myself I think.

kbs2244 · Jul 6, 2017

I would skip the ridge caps.
Install the side he wind comes from 2 inches past the ridge and push the other side tight against it.
Same with the closure strips, skip them.
Just cover the SF.

Not drum tight, but it wasn't bone dry before.

You are not building something your grandkids will inherit.

Adk Mike · Jul 6, 2017

I've fixed a couple buildings like that. I'd run 1by4s across the roof 2 foot apart. Let them hang out a ways. Sheet it with metal roofing into the 1by4s. The low spots shim it up so things are level. When your done box in the over hangs. It would last longer than you will.

Bert_ · Jul 6, 2017

Adk Mike said:
I've fixed a couple buildings like that. I'd run 1by4s across the roof 2 foot apart. Let them hang out a ways. Sheet it with metal roofing into the 1by4s. The low spots shim it up so things are level. When your done box in the over hangs. It would last longer than you will.

^ This. Around me I haven't seen anyone shingle an outbuilding, other that a garage next to the house, for years. Metal is the way to go.

Platonic Solid · Jul 7, 2017

SALIV8 - I've already put Felt Roof Deck Protection (linked) down. Though far superior, I don't think this structure is worthy of grace ice and water shield.

Platonic Solid · Jul 7, 2017

I'm just going to go ahead and use standard roll roofing (linked). I'll just have to see what I can do to reduce the inevitable wrinkle that will happen at the arched peak.

Platonic Solid · Jul 8, 2017

Progress and misc. garage pics: (all linked to larger images)

I was talking to a contractor while standing in line at Home Depot. He said when I'm ready to tear it down, I should contact one of the companies that reclaims old wood and they'll pay me to take it down. Now that sounds like a major win :thumbup:

Platonic Solid · Jul 25, 2017

Finished the roll roofing. Now I'm wondering if it would be worth digging a trench against the exterior walls and putting a 2ft high perimeter of pressure treated plywood in the ground to slow down the decay process.

(This has to be in the running for the most pathetic excuse for a garage on this forum.)

(as usual, all images linked to larger pics)

Covered in 3/8 plywood as there were too many large gaps and holes.

I left the trim pieces off as the eves were all filled with mouse nests and it smelled something nasty.

On this side of the building I can climb onto the roof from the truck bed, which made things a bit easier.

Apparently the square area on the wall under the large window used to hinge outward as there are hinges at ground level.

I was originally only going to do half the roof, but once I got up there realized that wasn't going to cut it. I only had to put plywood on one half. Total material cost $482. Total time about 70 hours. In hind sight, I would do regular shingles to avoid the mess of dealing with all the roofing adhesive.

Platonic Solid · Jul 30, 2017

So this is what happens to a wood floor when you leave a large folded tarp on it for 20 years. The wood in that area is like a sponge.

ford33 · Jul 30, 2017

Why did you save it?

I think it subtracts value from the property and should have been torn down. The house behind it looks nice and then people see this poorly maintained shed and think less of the property. But since you already have worked on it you have put lipstick on a pig. You did not add value to the property.

Stuart in MN · Jul 30, 2017

eh, I've seen worse.

If it keeps the rain and weather off your stuff, it's worth keeping it until you have the funds and time to replace it.

As a teenager I did a roll roof replacement on my parents' back porch, that sure can be a hot and sticky job.

Platonic Solid · Jul 31, 2017

ford33 said:
Why did you save it?

I think it subtracts value from the property and should have been torn down. The house behind it looks nice and then people see this poorly maintained shed and think less of the property. But since you already have worked on it you have put lipstick on a pig. You did not add value to the property.

I'm buying time while I clean it out. If I'd known it would take me 70 hrs to complete I probably wouldn't have done it. On the other hand, it's certainly better than this:

The tarp was only on there for a week. Since the tarp is so huge I had to fold it in half. Must be some holes in it cause when I took it off, about 5 gallons of water poured out. (This is the tarp that was stored on the floor.)

Platonic Solid · Jul 31, 2017

I figured something else out. While cleaning it out yesterday, I was getting tired of ducking me head every time I go in and out of the garage. Looking at the simple cable - pulley - counter weight system, it hits me - the floor isn't attached to the building and the building is sinking into the ground, thus the counter weight doesn't travel as far as it used to. The counter weight travels about 3.5 ft, thus the approx 12 inch gap at the top of the garage door tells me the building has sunk into the ground about 6 inches.

kbs2244 · Aug 1, 2017

Time for a new PBS series.
"This Old Garage."

Platonic Solid · Aug 2, 2017

kbs2244 - Great idea! That would be a big hit.

I can't believe I'm actually considering lifting this thing. Ford33's comment on property value got me thinking. Property value only matters if you're going to sell or refinance and I have no intent on either. If I tear it down and replace it, I would be increasing the value and my property taxes would go up at least $75/yr. Not exactly huge but it's not free.

It would be kind of like a "rat bike" or "rat car", except it's a "rat garage" (which is an extremely appropriate name for this garage right now).

TractorJeff · Aug 2, 2017

Fix it up!
Its a joke now a days as everyone is in the "Its old, Throw it away" mindset!

Stuart in MN · Aug 2, 2017

Platonic Solid said:
it hits me - the floor isn't attached to the building and the building is sinking into the ground

That would explain the wonky roofline.

You have nothing to lose by trying to jack the thing up. About ten years ago I helped my neighbor out with his garage; with his bottle jack and my floor jack we were able to lift up one corner that had sunk, put in new sill plates and sistered some studs, and got it looking halfway decent if you stand back ten feet and squint. It's still standing today.

Platonic Solid · Aug 3, 2017

I think I figured out the purpose for the odd fold down door on the side under the window. I think it's to bring wood in for a wood stove as there is a covered chimney hole in the back.

80 Year old 12x24 detached garage roof repair question

Well-known member

Well-known member

Well-known member

Banned

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Banned

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member