could somebody please tell me why some roofers put down 1x4 on the roof before the metal and i saw one the other day that had took old stuff off and put new paper down and then put the metal down.i have asked a few around here and one says no problem other say i wont do it like that.whats the good or bad?

 

I put the metal roof down on new felt paper all the time.

 

thank you.what if you dont take the old off,how would you do it?

 

What do you have on the roof now??????

 

14 year old shingles.

 

Id take it down to wood. Check it all . New 30lb felt then the new metal roof

 

thank you for your help.

 

The old timers around here insist on putting down strips for metal roofing. They claim the metal roofing causes condensation to form on the bottom side from the temp difference outside vs inside. I don't see how thats an issue if you have a good layer of tarpaper in place.

I'm with Ed on the recommendation to use of 30# tarpaper. Don't give in to the temptation to go over the shingles either. Rip everything off, check the sheathing, replace/renail as needed and start from a bare deck.

I will tell you one reason using those strips stinks. If you live in an area with flying squirrels, those little *******s will figure out a way under the metal and drive you insane trying to get them back out. Our cabin was done that way. One guy insisted it was bad letting the flying squirrels live in the chimney cleanout. I really didn't mind them being in there. He blocked them out with metal screening and they decided to chew under the roof. I evicted them from the roof and they are living in the chimney again. *sigh*

 

nice thread!

i am needing to convert to metal roof on this building away from the shingles that have been up there sicne about 1974 and are severely deteriorated and have been leaking for a long time, ive had to remove and patch in big sections with new shingles and aluminum roll due to large sections slipping down the roof somehow

so i am tired of shingles and this building is just too large for shingles, spending thousands on shingles every couple decades or less is not good imho



luckily the roof is based with good old strong lumber boards and they look good still but if i find any bad spots then ill repair with the same thickness of course, no big deal at all



so 30 lb felt paper is the way to go?

thats good to know


anything else would be great to learn regarding prep and so on for metal roof conversion


we dont have flying squirrels up here but we have the damn red ones and they will get in your attic and tear up ALL the insulation into a big ball in the attic
and they will even sometimes scratch through the sheet of drywall, all the way through!



its not funny at all..

it seems that squirrels of any color are bad lol


thanks

 

One thing to remember when changing from shingles to metal roofing - metal panels come in certain diemensions. If a roof is out of square, it may not be overly noticable with shingles which are easily trimmed to fit. The metal also come in standard widths. A little measuring and thought about how to install the panels can mean the difference between a great looking roof and one that isn't.

Also a metal roof isn't maintence free. A galvanized roof usually needs painting after 10-15 yrs and every 5 or so yrs thereafter. The new "painted" metal roofs advertise lifetime finish but in reality they will propbably need painting after 20-25 yrs. I have seen a few that the color had drastically faded in less than 10 yrs.

 

I am putting on a metal roof and am about half done at this time. I used 30lb. felt under the metal because the manufacturer of the roofing recommended it in the instruction literature. But I am curious why is it needed?

Also the half I have finished I rolled the felt in a horizontal direction as instructed but found it rather difficult. Could I roll the felt up and down in the same direction I am putting the metal on? The roof is 18 feet from ridge to eave.

 

some roofers use 1x4 to attach the metal if there is no sheeting or laying over old shingels. Some say you can lay metal right on top of the old shingels. I guess it just depends on what you want.

 

The skip sheathing just lets the metal 'breathe'. Felt is used under the metal because the manufacturers don't believe the roof will be installed corectly. Hence, the felt may keep the leaks from showing in the house.
I learned tin roofing many years back, and never saw a need for felt. Still don't.

 

Putting down slats over existing shingles and then adding the metal roofing saves having to remove the old roof. I agree though that it is better to remove the old roof and install felt. having said that, I've noticed roofers around here running felt vertically or from peak to eve rather than horizontally or parallel to the eve.

This would not be a good way of running felt under your metal roof. The metal may sweat and "rain" on the bottom side, and the water will probably meander it's way down the deck and could easily get under the felt if it is installed up and down instead of across.

If they remove the old roof we need to look at the decking.

Here in Alabama rafters are commonly spaced at 24" OC, give an inch or two either way. I've seen nails driven in as close to level as you can get to try and hit a rafter and hope the nail will keep the decking up. The decking material can either be 3/8 CDX, 1/2 CDX, 7/16 Waferboard or 3/4 pine or oak board (slat or T&G) decking. If your house was built in the 70's there's a good chance it's 3/8 decking. The decking may be pine or western cedar. If it's the later then there's a good chance the laminates or separating because the glue they used were of poor quality. If this is the case you'll either need to add new decking or use the slats to support the metal roof.

If the decking is good then we need to look at the roof and see if it is like the surface of the ocean. If you look up at the roof and see dips and high spots on the roof then this may be a concern if you install the metal roof directly to the decking. Whether or not this becomes a problem will depend on the type of metal roof you're using. With slats the roofer may be able to use shims to level it before adding the metal. They make metal pieces that can be installed along the eve and gable to close in the openings.