How to fix leaks in metal shop roof

[JCasper]

I have some leaks in my shop roof. This is a shop that my Dad built back in about 1978. It has a metal roof that is nailed down. It has some leaks that I'd like to fix. The metal is in good shape, not really a lot to go wrong with it. I'm thinking that I will pull all the nails with the deteriorated rubber washer and replace with new screws. Am I missing something here or is this a good way to go?

 

[seafish]

About 15 years ago I salvaged the 30' x 60' metal roofing and trusses on an old fire station that we were taking down for replacemtn. I then built my woodshop to that size in order to reuse the roofing. While I DID use the trusses, I finally decided it was NOT worth reusing the metal roofing. I made that decision NOT becasue the roofing was in bad condition (it was decent grade architectural metal roofing in decent condition, but I did NOT want to go back and make sure that every single nail hole would be refilled and then miss one or two and have to go up and seal them off again. Went with the new metal roof and have not looked back...used the old pieces to keep the lumber dry in the lumber yard.

That being said, in your case, it mostly depends on where/how it is leaking now. Also, the problem might well be pulling the nails without further damaging the roofing...otherwise noting wrong with the idea.

 

[ScottLewis]

Pulling old nails can cause more harm than good. They are often screw type that don't pull easily. How about coating the nails with an elastomeric or asphalt sealer like Henry's etc.?
Done systematically, it shouldn't take as long as re-nailing all the panels with new nails, assuming you could successfully pull the old nails.

 

[JCasper]

Pulling old nails can cause more harm than good. They are often screw type that don't pull easily. How about coating the nails with an elastomeric or asphalt sealer like Henry's etc.?

I've done that and it did help, but I still have a few leaks and they're hard to track down.

 

[JCasper]

About 15 years ago I salvaged the 30' x 60' metal roofing and trusses on an old fire station that we were taking down for replacemtn. I then built my woodshop to that size in order to reuse the roofing. While I DID use the trusses, I finally decided it was NOT worth reusing the metal roofing. I made that decision NOT becasue the roofing was in bad condition (it was decent grade architectural metal roofing in decent condition, but I did NOT want to go back and make sure that every single nail hole would be refilled and then miss one or two and have to go up and seal them off again. Went with the new metal roof and have not looked back...used the old pieces to keep the lumber dry in the lumber yard.

That being said, in your case, it mostly depends on where/how it is leaking now. Also, the problem might well be pulling the nails without further damaging the roofing...otherwise noting wrong with the idea.

I understand what you're saying, it might do more damage pulling the nails. I'll look into the cost of new roofing and see if it's something I want to invest in this summer.

The shop is 30x36.

 

[Bill Stockard]

We had a similar leak problem with a 80'x 120' pole barn built in the mid-60s using corrugated galvanized metal roofing. At the time it was built the metal had to be in two sections to cover the roof and was nailed on with lead head nails. Over time water would seep between the panel joints and seams and the nails loosened and leaking badly. We finally cured the problem by replacing the roof. Our roofing contractor ordered ~44' long sheets of corrugated galvanized roofing (I don't remember the exact length) from a metal building and roofing supply company, sealing each lap with "tacky tape", and using screws instead of nails. It hasn't leaked a drop over 10 years.

Bill

 

[Hoefler]

You will find where the nails are leaking, the wood is rotted to the point it will not hold a nail. The best thing you could do, as suggested above, replace the metal and use screws.

 

[jgillott]

Just another thought for you on this subject. One of our fire stations has a metal roof that had persistent issues since its construction. In the early 2000's we had it sprayed with this coating from Conklin roofing systems.

http://www.conklin.com/content/products/rs/bospraypolyurethanefoam.cfm

I don't remember the exact cost, but it was much less expensive than having the roof replaced. With a bulding as small as yours, it may be worth looking in to, especially if the material itself is in good shape.

 

[Bob V]

Joe, does the roof have insulation or a vapor barrier of some kind? Do you know what the pitch is?
What can happen is that after years of the metal expanding and contracting the nails/screws can become loose from the movement of the roof. It can also cause the holes to elongate, causing a leak. The best steel roofs have no exposed screws and the brackets that hold the roof down are slotted. I worked for a guy that did that type of roof that the seams where double rolled in place to make the whole roof one piece. It was a cool system and you only had to worry about the peak and any penetrations that went through the roof (vents and flashings). If it where me I would probably go up and do as much repair/calking and try that first, but you need to find the leak(s) first. Then, if that didn't work, look at a coating as an option.
Myself, I like comp roofs over metal, unless the roof fasteners are concealed, all exposed fastener metal roofs will eventually leak. A friend is building a 80'X120' shop, after doing all the pricing he decided on stick framed with hardie plank siding and comp roof, it was cheaper than pole barn style.

 

[JCasper]

Thanks for all the responses. This was put on around 1978, they are 1 piece sheets, but are nailed down. I had thought that there might be a problem with rot because of the leaks and wasn't sure if a screw would hold. It might be best to just replace it.

I'll try caulking it again in a few spots, but I don't like getting up there unless it's dry. It's a long ways down if you started to slip.

BobV, I think the pitch is 3:12, maybe 4:12, I'd have to go look and measure. It is a stick framed structure, but metal side and metal roof. There is no insulation or vapor barrier.

As to your friends shop, stick framed was really cheaper? I'm looking at buying the 10 acres next to me and putting a riding arena and horse barn on it. I'd be looking to build something about that size, but with a 36' wide shed roof off each long side for stalls, storage, etc.

 

[Bob V]

IF!! you are going to have a cement floor the stick framed is cheaper. No floor then pole barn is the best way to go. The price is for material only, labor needs to be factored in, unless you are doing you own work.

 

[B.G. Smith]

If you decide to re-caulk, consider using one of the RV roof sealants, they are mor resilient and last much longer than the asphalt type stuff. bg

 

[suzannethompson]

Hi JCasper,
Well I am living in a metal buildings detroit from a long time and know these problem quite very well. Its a common problem with metal roofs. The solution is also not much complicated. First, clean roof of debris and clear all drains. Tighten the fasteners and replace if any are missing. Remove the rust before moving to power washing. Buy a good polyprene and apply it. Apply elastomeric and let it dry. Give a last finishing coat of elastomeric and you are good to go.

 

[ALSAN]

There is a way to remove the nails that will not hurt the steel ie.. dent etc you need to make this tool-buy a pair of horse hoof nippers and a auto dent removal tool/ the slide hammer type/ weld the slide hammer to one handle on the nipper - to use open the jaws of the nipper and close behind the nail head -slide the weight on the dent tool up while holding the nipper shut . The nail will pop out sometimes it takes two wacks but it works
I have one of these tools hanging in the garage if you need a picture pm me with your email and I will send a pic sorry I dont know how to post pictures to this site -give me a set of blueprints and the materials and I will build you any building you want thou

 

[BDaugherty]

The tack tape used to seal the seams works wonders for patching holes.

 

[sluper]

There is a white polymer that is good for 7 years, it can be ordered on line from Home Depot, or you can find it at most good hardware stores. Sold in 5-gal buckets that is applied with a paint roller. This is not the cool seal that is applied to manufactured houses, that is pretty thin so be sure you get the get the white polymer I have used it on metal that was on our house but now is on an equipment shed. It was screwed booth times, "NO LEAKS" in the couple of years since I put it on. If you replace the metal check out the "Galvalum" (Spelling) it is cooler than the galvanized and will last much longer.