BajaNomad

Advice on garage roof please

Doug/Vamonos - 8-24-2016 at 07:13 AM

Hi. I'm building a new place in LA Bay. My garage is 16' x 24'. The roof will be plywood with the standard rolled roofing. The pitch is minimal - a little over 1/4" per foot. Pretty much what every other garage looks like that I have seen. In previous builds I've just rolled the material in place, nailed it every foot, and sealed the edges and overlapping seams with Henry's roofing adhesive. Seems to work fine. But would it be better to hotmop the plywood first to enhance the durability in case water or moisture gets past? Actually I wouldn't hotmop with the hot aphalt but use one of the roofing primer sealants that I find at home Depot. Or am I over-engineering this? Does anyone use a propane torch to adhere the roofing? Thanks.

rts551 - 8-24-2016 at 07:15 AM

Have you ever considered using a metal roof. At least over on the Pacific side, Punta ABreojos, the rolled roofing never seems to last long.

David K - 8-24-2016 at 07:21 AM

Suggest you talk to Bedman (Camp Gecko) as his roof-over set up looks pretty solid.

DENNIS - 8-24-2016 at 07:26 AM


Don't hotmop the plywood. If in the future you want to re-roof for whatever reason, you won't be able to.
Torch-down roofing works super well, but practice first. It can be unforgiving.
I just did another roof with lap-cement. It works well as long as the base is straight and smooth. Roll roofing shows most uneven imperfections below the surface.
If not too late, maybe add a bit of pitch to the roof. The faster water runs off, the longer the surface will last.
Are you sure 16 feet is deep enough? Better measure your vehicle.

woody with a view - 8-24-2016 at 07:26 AM

Use roof felt first. If you never want to worry about it look up TPO roof membrane.

larryC - 8-24-2016 at 09:41 AM

I have used rolled roofing in the past and if done right it will last 10 years or so. Less time if not done right. The last garage I did in metal, easier and lasts a lot longer.

Russ - 8-24-2016 at 10:37 AM

We use maxiteja (sp). It's a composite material that comes in 1 meter by 2 meter sheets and is screwed down to the plywood or rafters. we use to be able to buy 1 meter by 6 meter or longer sheets of the same material we called lamina. Note the above about plywood quality whether you use rolled roofing or other material bad / cheap plywood can really cost a lot to replace. Here are some photos of my patio roof. My garage is the same using lamina. So far no storm has done any damage. I wrapped the patio roof in front for a little shade during the sunrise. I think it also helps break the storm winds.



willardguy - 8-24-2016 at 11:50 AM

Quote: Originally posted by rts551  
Have you ever considered using a metal roof. At least over on the Pacific side, Punta ABreojos, the rolled roofing never seems to last long.


I'll go with ralph, after 10 years our galvanized roof (the whole house is metal) looks exactly the same as when it was built, (this is on the cortez side)

AKgringo - 8-24-2016 at 12:54 PM

The OP stated that he only has a 1/4 inch per foot drainage. Since there is almost 100% chance that the rafters will sag at some point, drainage is a real problem in a downpour.

I feel that an impervious membrane is mandatory either as a roof surface, or under it.

Doug/Vamonos - 8-24-2016 at 02:17 PM

Thanks for your input. In our campo everyone builds a strong roof to place a pila/tanque/tinaco (whichever is your preference) on top. I will also mount a dozen solar panels up there and occasionally sleep up there. I weigh 230lbs and my dog weighs 85lbs so it needs to support all of these things. So the steel (can't walk and sleep on it) and the plastic doesn't work in my case. I think I'll increase the pitch and add a layer of roof felt under it like Woody suggests.

[Edited on 8-24-2016 by Doug/Vamonos]

woody with a view - 8-24-2016 at 02:47 PM

I had to seal around the water tank since water has found its way thru under it. just some stains on the joists, nothing major. two tubes of Henrys. the rest of it is holding up nicely.

use felt-it adds a layer of cushion for those nail heads that don't get pounded down flush.

Bob53 - 8-24-2016 at 04:35 PM

Afterwards, put a couple coats of white elastomeric roof coating and that will extend the life of your roof and deflect a large amount of sun's heat.

http://www.homedepot.com/p/Henry-4-75-Gal-587-White-Roof-Coa...

larryC - 8-24-2016 at 04:35 PM

Quote: Originally posted by Doug/Vamonos  
Thanks for your input. In our campo everyone builds a strong roof to place a pila/tanque/tinaco (whichever is your preference) on top. I will also mount a dozen solar panels up there and occasionally sleep up there. I weigh 230lbs and my dog weighs 85lbs so it needs to support all of these things. So the steel (can't walk and sleep on it) and the plastic doesn't work in my case. I think I'll increase the pitch and add a layer of roof felt under it like Woody suggests.

[Edited on 8-24-2016 by Doug/Vamonos]


You didn't mention in the original post that you wanted a water tank and a patio on your roof. Maybe a torch down roof will work for you. Ask Robt and Pam over at beach Bob's old place what they had to do to get a water proof roof. As I remember it was lots of rolled roofing and tar.

mtgoat666 - 8-24-2016 at 08:27 PM

Last time I built a water proof deck, I used a paint-on (via roller) material (over quality plywood deck) that was waterproof and walkable (it went on in 2 coats, set up with flexibility like rubber, and had some additive that provided surface roughness for traction). Don't remember the name of it, bit it held up for over 20 years in direct sun and weather.

If you want a walking surface, use the specialty products made for foot traffic. The normal roof products are not intended for frequent foot traffic.

Put your solar mounts on first so your roofing product is properly incorporated with flashing.

If not using the roof as a deck, then increase the pitch, and 99 percent of your leak risks will go away.
Quote: Originally posted by larryC  
Quote: Originally posted by Doug/Vamonos  
Thanks for your input. In our campo everyone builds a strong roof to place a pila/tanque/tinaco (whichever is your preference) on top. I will also mount a dozen solar panels up there and occasionally sleep up there. I weigh 230lbs and my dog weighs 85lbs so it needs to support all of these things. So the steel (can't walk and sleep on it) and the plastic doesn't work in my case. I think I'll increase the pitch and add a layer of roof felt under it like Woody suggests.

[Edited on 8-24-2016 by Doug/Vamonos]


You didn't mention in the original post that you wanted a water tank and a patio on your roof. Maybe a torch down roof will work for you. Ask Robt and Pam over at beach Bob's old place what they had to do to get a water proof roof. As I remember it was lots of rolled roofing and tar.

Chrish22 - 4-12-2017 at 11:00 AM

I just completed roof repairing campaign under the expert guidance of Robbie Malan, and now I feel safe to move into my home with kids and family, once again.

Phil C - 4-12-2017 at 02:38 PM

Find a roofer, take him fishing.........

Check your U2U

[Edited on 4-12-2017 by Phil C]

Doug/Vamonos - 4-17-2017 at 05:49 AM

Old post. Came out fine. Thanks.

DENNIS - 4-17-2017 at 07:04 AM


I was going to say, use this stuff, but as mentioned....old thread, and I already did:

http://us.henry.com/roofing/adhesives-and-primers/203-cold-a...