Wednesday, March 12, 2014

Working With Sheet Metal



I'm putting up a shed and using sheet metal for the roof and 2 sides (ends will be open). Goal is to build a short term (5 yrs) inexpensive shed to cover equipment from the weather. I found 26 inch by 12 foot sections of corrugated sheet metal at a lumber store for $12.50 each....it is the cheapest I've found. I have several questions as I've never worked with sheet metal before.
How much overlap is required on roof and sides?
Can I get by with cheap screws or do I need to use sheet metal screws (again budget is minimal)?
Are special washers required?
I need to cut a couple sheets diagonally. What is the best way to do this....someone mentioned using a circular saw with the blade backwards. Sounds easier than tin snips??
Is $12.50 for a low grade 2x12 sheet about as low as one can buy corrugated sheet metal?

Most corrugated only has to be overlapped one roll.I would seal with silicone though.Screws should not be a problem (especially since it is a relatively short term thing).You do need rubber washers to keep the screws from leaking unless you can put faith in a tube of silicone caulk. Cutting method is correct.Be sure to wear long sleeves and a face shield. The shavings are nasty.Cost is relative to the area and demand. Good luck.

John, You might do some checking. I just resided a shed for the Mother-in-law. A local metal dealer let me order the 5 rib steel siding cut to the inch. This sure made it quicker for installation and the only waste I ended up with was cutting the angles for the gables.
I used the screws with neoprene washers that are supposed to start without drilling but it was quicker for me to use two drills, one with a drill bit and the other with a driver.
Good luck

John,
I'm not really sure where that backwards blade thing got started.
I have always used a proper metal blade in a circular saw but tried it when I first heard that wive's tale about using a regular blade backwards.
Maybe it's just me, but all this did was burn, bind and knock off some teeth on my blade.
A proper metal cutting blade is not that expensive
You can sometimes rent a guillotine cutter where you purchase the metal.

I saw that nails with washers are much cheaper than the screws. The guy at Lowes said all old barns were build with nails and they should work fine. I'm a little worried about driving nails in the high end of the corrugation. Wouldn't it either tend to slip or at least pound the corrugation flat in that area??
Would nails work fine or do I really need to use screws?

I agree that the correct blade would not be that expensive and probably safer. Did my father-in-laws 50x100 barn with the backwards blade thing and never lost a tooth.Suggest you buy the blade though. You should not be nailing (or screwing) in the high end of the corrugation as it will not be sitting on whatever your nailing to in the high end.What you are nailing to will be running across the waves. Nails will work.

I wholeheartedly agree that you should avoid using a saw blade in the reverse direction that it is designed and engineered and intended to cut. Having dealt with contractors and diyers for several years at my fastener supply house I have heard many stories about serious injury from misusing saw blades in this fashion. Purchase metal cutting blades, but make sure that they are engineered to cut the guage of the sheet metal you are using.
Screws will in the long run perform better than nails for your type of application. Manufacturers of corrugated metals usually recommend screws for the installation of their products; and some even have proprietary screws made just for them and to their strict specifications. Screws, in the most general of terms of course, have ratings in four main strength catagories; tensile, yield, shear and pullout. So do nails; but screws, in most cases and with some exception of course, outperform nails of the same sizes in nearly each catagory.
The other advantage to using screws is that they come in a greater variety of base materials and coatings which will help extend the life and reduce maintenance and upkeep of your project; by preventing rust and prohibiting hydrogen embrittlement.
It is important to use either rubber or neoprene sealing washers in your type of application. Doing so, and installing them properly, will eliminate or greatly reduce the chance of leakage, but they also serve as isolators or a barrier between dissimilar metals. One of the major reasons, there are of course many reasons, fasteners fail is because there is a chemical reaction between the different metals that the nail and/or screw is made from and that of the material it is in contact with. This reaction is only worsened and accelerated by the weather elements.
There are many inexpensive screws available for your application that have numerous drive head selections (phillips, hex, torx, etc) and excellent coatings with factory mounted washers. The fastener industry calls these SEMS which stands for preasSEMbled. SEMS are vailable in nearly every popular size, coating, and with a variety of washers. A word of caution: It is possible to overtighten some types of SEMS and damage the washer which will reduce it's function. The better SEMS will have a rubber (or neoprene) washer under a metal washer. That metal washer (often called the 'cap' of a SEMS) prevents damage to the rubber or neoprene when the screw head is spinning and being driven tight, but that metal washer also helps extend washer life as it shields the material from harmful UV rays.
If I were doing this project I'd get stainless hex headed SEMS with rubber washers and stainless caps. Being stainless they can be pricey and a bit brittle but they will outperform any comperable nail and you'll never have leakage or rust spots or rust runs.

PS: Should you decide on using nails instead of screws there are rubber and neoprene washers, with and without metal caps, that are sold seperatley and can be utilized with nails. They can be round, square, hex shaped, stars, and for tight spaces - oblong. Some even come in colors. Use a good ring shank nail, and IMHO an epoxy coated one. It will bond extremely well with the base material from the heat of friction when driven in.
Also: There are nails available with factory installed weather proof washers. These are KEPS which stand for shaKEProof. The washer will not come loose and slide down the shaft from vibration when struck by the hammer. They must be driven as straight as possible for the washer to properly seal.

I often purchase unwanted, leftover, etc corrugated and other types of metal siding and roofing from contractors and building supply houses for resale at my ornamental and architectural salvage yards. Over the past couple of years I've noticed warning signs near the sales counters about not using circular saw blades backwards, and some of the MDS also have a warning against doing so. A MDS is Material Data Sheet. It's a little bit like those MSDS Material Safety Data Sheets for hazardous chemicals that warn against spill, fire, and health hazards and tell you what to do if any of that stuff happens. MDS are slapped on some products in a self-stick packet that looks like a packing slip thingy. MDS tell you what the stuff is made out of, where it was made, and other things like what to wear when cutting it ... such as eye shields and dust masks for example. Some of the siding I've bought for resale had MDS packets stuck on it that when opened up and read warned against reverse saw blade cutting.

Kinda looks like I opened a can of worms with my reply. Let me put a disclaimer to my original post.
Although it is POSSIBLE to cut sheet metal with a circular saw blade installed backwards, It IS NOT recommended and is a safety hazard. Lots of things we did in the past (such as asbestos removal ) have proven to be hazardous and this practice is one of them.

I worked for a time makeing that corrugated sheet metal.
If you look when you get it . Most of the time its like two sheet's are like together. Thats cause they are fed in the roller two at a time. Also there is a side that should be the over lap and a side thats the under one. It does work a lot better if you can drill the holes for nails are screws with the rubber washer on them. You do want to put them on the ridge of the metal not down in the little valleys like . If they are not to heavy Ga you can cut them with a snips and bend it back right
My .02 cents
ED

Cutting sheet metal.
Using any Blade with teeth to cut sheet metal that thin diagonally is big trouble.
Go to your hardware store and ask them for a 7 inch dia. 1/8 thick reinforced cut off DISK (for METAL) that will fit your saw READ the SAFETY INSTRUCTIONS
Notes:
The edge you cut off will be very sharp.
The sparks from the disk can set your lawn or something on FIRE.
Price about $5.00
I think the over lap is 1 inch for your 26 width.
With one inch on each side that will give a 24 inch spacing for the studs.

Hiyall,
I cut steel with my chop saw, and when the blades are too small for cutting with it, they fit perfectly in my 7 inch circular. I then use them for odd peices that cannot be clamped into the chop saw, stuff like cutting across a sheet of corrugated for example. Be sure to secure the work, and BE CAREFUL.
You might be able to get the used blades from a welder or other metal worker. Not everyone uses this trick.
I have a question, does anyone know of a jig to cut 2X4's so that they are scalloped like a piece of corrugated, so that you can screw into the top of the waves, or is it best just to screw into the bottoms?






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