Metal roof question - Contractor Talk - Professional Construction and Remodeling Forum

Burby · 12-11-2008, 09:29 AM

5 v-crimp galvalum

This roof is on a GC's house, no joke, he passed away last year, but none the less. The roof is approx 20 years old. It is the first house him & his wife built & built together so she is keeping it, no questions.
2800 sq ft on the coast. The house is a gabled 12/12 roof with wrap around porches. Porch roof is a 3/12 with the needed hips as well as one added hip, for the only purpose I can figure out, is to divert the water coming off the 12/12 into the valley directing the water away from steps below. The 12/12 runs are 17 ft, so that is a lot of water runing down them sheets in rain let alone heavy rains.

In the 33 years of my construction experience I have only installed 2 or 3 metal roofs and that was over 20 years ago up in New England. Still, when installed, it was done over a sheathed roof with 30 lb felt under, (I believe it was anyways or what ever metal roofing called for then)

I was contacted by this H/O because of all her friends she asked, all suggested she contact me, as well as referals from 2 other homes on her street I did extensive work on a few years back.
Her Husband with all due respect should never have been a Residential Builder.
I think the roof should be totally removed & properly installed & will list why after questions below. Answers to questions may lead to tear off anyhow.

For Roofers who install metal roof and have metal roof & code exp approx 20 years ago.
The roof question is approx 20 years ago, did building codes allow for metal roofs to be installed over nothing more than rafters with 1x4's every 18"? (no roof sheathing) Especially on the coast.

This metal roof is amazing it is still on the house today.
Fasteners - 3/4" screws, installed on the apex of the V, every 18" with the rakes the same and further apart in some cases. Roof eaves, 1 screw on every V only, nothing on the flats where should be.
Overlaps - No bead applied to prevent wind blown water from entering the attic space.
Valleys - metal is approx 16" w/6" exposed. Keep in mind most of these valleys are in areas of run off from the 12/12 connecting to them. No sealing of any kind at the sheet ends onto the valley flashing. Some of these valleys that must have had leaks over time you find latex and or silicone caulking applied to try & divert the water from running under. Both types of caulking should never be used on the exterior, especially in this application.
Chimney - 40" wide - No cricket, flashed on 4 sides. The 12/12 run into the back of the chimney is 12 feet. The 40" gets all that water running down the 12 ft run. Metal has rusted out from debris sitting in between rains. Tar, roof cement patch, ect has been added over the years when leaks occured instead of building a cricket.
Hip & ridge caps - There is a pc of what looks like cheesy weather strip under. It is not a weather proof type by any means, black foam type approx 3/4 x 3/4", real soft & porus.

What got me up there looking around was the vent pipe flanges began to leak or believed so until I got up there, walked around and saw all I did, which lead me to looking further into the matter.
With codes if 50% of a roof needs repair, the entire roof should be replaced. Which if code did allow for metal to be installed over strapping instead of solid sheathed roofs, she would now need sheathing if the roof is removed & replaced properly as should be regardless.

The sheating requirement is the biggest thing back then.
Regardless at the very least it needs proper sealing, proper fasteners, cricket built, ect.
She stated she will not take a needed loan for repairs. lol, well I said I hope you have lots of money. But at the same time she did not realize the amount of work this house needs, the roof is the just the tip of the iceburg.
New windows are needed & ordered, but after doing some repairs we discovered more covered up wood decay in every place the house has been worked on over the years.
You look at the outside of the home & it is a well kept, beautiful home. Open up most any place that i have & you can tell all the times it was repaired because of each improper repair made causing the need for the present repair.
It is a painted cedar siding home now, cedar siding replaced the cypress siding previous on the home. A few walls still have cypress, not many.

Normally I would walk away from a H/O as this. Fix it the proper way or find another to make needed repairs.
But, she lost her husband of 36 years recently. I know what this is like as I lost my wife of 30 years in 2004.
It is the first house her & husband built so has this sentimental value to it.
So (kicking my own azz) if i can help her I will & would like to. For this being a Builder's home, I never would have believed the findings we have uncovered.

Thanks in advance

tinner666 · 12-11-2008, 12:23 PM

18" spacing is OK.
No underlay is OK. I see the call for it nowadays, but not the reasoning.
Last month's roof:

Crickets are best, but it could survive without it at 40" x 12'.
I hate screws on the flats and don't do V-crimp if I can get out of it.

Valley width isn't as critical as the detailing. A soldered lock strip and hemmed outer edge would be fine. ( As long as the panels aren't hooked tightly. I leave 1/2" from fold and locking lip.

Burby · 12-11-2008, 12:54 PM

Thanks for responding Tinner.
here are some of the pics if attached correctly, how do you get to post the pics in the post?

I will try this and see how it works. If it works I will then come back and explain the pics listed

Burby · 12-11-2008, 12:58 PM

well I guess that was easy.. lol

this house as I mentioned is right on the coast or better yet on the Charleston harbor. So stroms, tropical and or hurricans are a real threat each year, let alone any coastal storm.
The overhangs do need to be evened out as well. They go from 2 inches to 10" around the house and looks alone not to mention wind catchers in storms. The screws penetrate the wood by only a 1/4"

tinner666 · 12-11-2008, 01:03 PM

Your last picture is an example of where to place a 'Channeled' Valley'. Not a 'regular' or 'W' type. Use the link and look for 'Channeled Valley' pics. http://rcs.si-sv2628.com/photo_album_list.asp?u=30

Those laps can work. Proper ways are either; Put 2-3 beads of sealant between the sheets, starting about 2-3" UP inside the seam. (It can NEVER be at the joint. That would promote capilary action and leaking.)
Or Hem the upper edge of the lower piece.
Or combine the two techniques.

tinner666 · 12-11-2008, 01:05 PM

"The screws penetrate the wood by only a 1/4"" Phew!

Not good.

Burby · 12-11-2008, 01:24 PM

here is a few more pics.
the keyword is is Properly detailed. As with any termination point and that is the problem here, only detail is flat with nothing to stop water what so ever when blown under. As well as notice the pic above where one roof dumps on the other with the open end of the ridge cap.

tinner666 · 12-11-2008, 01:25 PM

That juncture in the 3rd. pic is something I could never explain. I can handle it and do it often 'by breaking each unit into seperate componets from the bottom up'.

tinner666 · 12-11-2008, 01:27 PM

"the keyword is is Properly detailed. As with any termination point and that is the problem here, only detail is flat with nothing to stop water what so ever when blown under. As well as notice the pic above where one roof dumps on the other with the open end of the ridge cap." we were posting at the same time and I was 'addressing' it somewhat.

Burby · 12-11-2008, 01:38 PM

Thanks again Tinner.
At first that is what I was going to do, added needed screws, (proper length)

lol, no joke, 3/4" screws, with the V being 1/2" or so that leaves only 1/4" into the wood, I can lift the sheets off where there are screws and what amazes me the metal is still on the roof.

Then add the needed beads of proper caulking, not latex or silicone, to seal all joints. I do know about where to apply the lap beads to prevent siphon effect.
I was just surprised to see no deck sheating under with a waterproofing barrier between both, per new codes, as well as 1995 boca codes and v-crimp specs.
If previous codes called for sheathing & a form of waterproofing between both, I was planning on addressing this with her, regardless of her decision.
I was hoping someone knew the codes for back then.
If not I will run into the permitting office in the morning to talk with the building inspector then speak with H/O.

Red Adobe · 12-22-2008, 09:13 AM

Wow
I feel for you. Just becarefull of pissing off the H.O. when talking about what you need to do to her late husbands "pride" even if it was done 20 years ago. ( Its common for folks with a metal roof to feel that its a forever "no maintnance" part of the home.

On the code issue.....if you involve the inspector much it could get ugly for the H.O since its not a decked roof.

dakzaag · 01-22-2009, 01:16 PM

Burpy,
I was interersted in the chimney flashing detail of this situation. Perhaps you have washed your hands by now, but if not I have a new chimney coming through an existing metal roof, (pole barn) so no decking but 2X4 perlins every 2'. Flashing sides and buttom are no problem, but the top looks like it needs a cricket to be done properly. Chimney is 28" wide and metal run above the chimney is at least 30 feet probably 4 12 pitch. Several things I dont like about the cricket idea is it opens up more seams and there is no deck to build off of.
Can someone help a poor mason out with this flashing detail?