Im looking at re-roofing my house with metal roofing panels.I like the idea of just putting it over my existing asphalt shingles however im getting conflicting info on how to do this.Some say to nail down 1x4 strips about 2 ft apart to attach the metal to others say its ok to lay the metal right over the shingles.Just curious if any one reading this has done this work.Also do you know of any good books or vids on this subject? Thanks .
Metal roofing?
- Thread starter bosco
- Start date
Rocky1
New member
Nailing the 1 x 4 is advisable.
-- Provides much more support than simply screwing it to your shingles and 1/2" plywood. Most sheeting on roofs is 1/2" 3 ply to boot, which isn't real sturdy.
-- Prevents bad shingles, or multiple layers of shingles from causing joints to NOT lay flat and seal properly. You can shim the 1 x 4 to make it flatter.
-- Allows some airspace underneath so it can breath. Otherwise, any moisture that happens to find a little dirt and gets trapped under the tin, can cause premature deterioration of the tin.
-- Not to mention, you may find the roofing manufacturer requires the 1 x 4, for any number of reasons, and should you ever need warranty on the metal roofing it would really suck, to not have it there. Personally, I'd check with them before worrying about what everyone else says. The rest of us aren't going to warranty your roof.
-- Provides much more support than simply screwing it to your shingles and 1/2" plywood. Most sheeting on roofs is 1/2" 3 ply to boot, which isn't real sturdy.
-- Prevents bad shingles, or multiple layers of shingles from causing joints to NOT lay flat and seal properly. You can shim the 1 x 4 to make it flatter.
-- Allows some airspace underneath so it can breath. Otherwise, any moisture that happens to find a little dirt and gets trapped under the tin, can cause premature deterioration of the tin.
-- Not to mention, you may find the roofing manufacturer requires the 1 x 4, for any number of reasons, and should you ever need warranty on the metal roofing it would really suck, to not have it there. Personally, I'd check with them before worrying about what everyone else says. The rest of us aren't going to warranty your roof.
guess
New member
screwing the 1x4's to the rafters then the metal to the 1x4's is the only way it will stay in high winds! The 1x4's need to be no more than 2 feet apart. I would put foam board between the 1x4's as well for added strength and insulation. I've seen it done other ways and it blows off!
jonthepain
New member
I thought that stripping the old shingles off my roof would be a pain, but they came off very easy, and my sons and I found some rotted wood that I was able to replace.
Of course it was 100 degrees when we did it...
you might save yourself some hassle in the long run if you strip the asphalt off first before installing the metal, in addition to any warranty issues the manufacturer might have with installing over another roofing system, not to mention the wind issues that guess cited.
roofing is he!! on shorts:
Of course it was 100 degrees when we did it...
you might save yourself some hassle in the long run if you strip the asphalt off first before installing the metal, in addition to any warranty issues the manufacturer might have with installing over another roofing system, not to mention the wind issues that guess cited.
roofing is he!! on shorts:
Rocky1
New member
Originally Posted By: boscoThanks guys. it seems like it would create indentations between the 1x4's under a load, such as snow or if you had to walk across you roof.Maybe the metal panels are a lot sturdier then I imagine.
You don't want to walk on the metal bewteen the strips, if at all possible bosco. You don't displace weight over a broad enough area, and yes you will bend the tin if you step between the 1 x 4s, especially if you step on the edge of sheet. Follow the screw lines where the 1 x 4s are when you walk on the roof. The screws also provide additional footing, tin roofs get really slick!
Snow load is a whole different ball of wax, weight is distributed over a much greater area, and typically won't cause a problem. I would say never causes a problem, but that's a pretty broad disclaimer, and poo happens. I've never seen it cause a problem anyhow, and having spent 25 years in ND, and survived the winters of the mid 90s there, I can assure you that claim isn't made lightly. There were a lot of roofs caved in a couple of those years, snow loads causing rafters to break and such, but you couldn't see any damage to the tin on standing roofs.
That having been said, there is a great deal of difference in the weight (thickness/strength) of different metal roofings and sidings. When you purchase, be sure to compare apples to apples in that respect. Some of it is MUCH STURDIER than others, but I still wouldn't walk out in the middle of it.
You don't want to walk on the metal bewteen the strips, if at all possible bosco. You don't displace weight over a broad enough area, and yes you will bend the tin if you step between the 1 x 4s, especially if you step on the edge of sheet. Follow the screw lines where the 1 x 4s are when you walk on the roof. The screws also provide additional footing, tin roofs get really slick!
Snow load is a whole different ball of wax, weight is distributed over a much greater area, and typically won't cause a problem. I would say never causes a problem, but that's a pretty broad disclaimer, and poo happens. I've never seen it cause a problem anyhow, and having spent 25 years in ND, and survived the winters of the mid 90s there, I can assure you that claim isn't made lightly. There were a lot of roofs caved in a couple of those years, snow loads causing rafters to break and such, but you couldn't see any damage to the tin on standing roofs.
That having been said, there is a great deal of difference in the weight (thickness/strength) of different metal roofings and sidings. When you purchase, be sure to compare apples to apples in that respect. Some of it is MUCH STURDIER than others, but I still wouldn't walk out in the middle of it.
The way (guess) said is a very good way and then you can walk on it. Get the extra heavy wt. tin at 80,000 lb.rip strength. Lowe's and Home Depot say there's is the heavy wt. but it is only 40,000 lb. We did our house in tin in Tx.and it is concidered class four roofing and it cut our yearly home owners ins. by 28%. ask your ins. rep if you get a cut in premium.
As mentioned...check the thickness of any metal You plan on putting on Your Roof and how long the warranty is good for.
Some Roofers reccomend taking off any old shingles while others say if You only have 1 layer of shingles You can put the tin down over it.Personally I would ask a Professoinal Roofer or even the experienced Guys at the Store You get Your metal Roof from and see what they reccomend?
If we ever get any more Storm Damage on our Roof the next time it gets replaced all the old shingles are coming off and I'll have a new Metal Roof put on also.
Another thing to consider is the Pitch of Your exisiting Roof...if its a 1-1/2 or 2 Story House with a steep pitch most Roofers put the braces that run opposite/horizontal to the Metal Roof for when snow or ice builds up it will keep the stuff from sliding off in large sheets and riping Your gutters off or falling off and hurting someone!
We have a local Older School that is a 3 or 4 Story Building....a few years ago the snow and sleet built up on it,when it thawed out big sheets of the white stuff slid off and damaged several cars and busted out several car windows parked below it!
Some Roofers reccomend taking off any old shingles while others say if You only have 1 layer of shingles You can put the tin down over it.Personally I would ask a Professoinal Roofer or even the experienced Guys at the Store You get Your metal Roof from and see what they reccomend?
If we ever get any more Storm Damage on our Roof the next time it gets replaced all the old shingles are coming off and I'll have a new Metal Roof put on also.
Another thing to consider is the Pitch of Your exisiting Roof...if its a 1-1/2 or 2 Story House with a steep pitch most Roofers put the braces that run opposite/horizontal to the Metal Roof for when snow or ice builds up it will keep the stuff from sliding off in large sheets and riping Your gutters off or falling off and hurting someone!
We have a local Older School that is a 3 or 4 Story Building....a few years ago the snow and sleet built up on it,when it thawed out big sheets of the white stuff slid off and damaged several cars and busted out several car windows parked below it!
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