Sheet Metal Basics - Parapit flashings BobLuland - Sep 29, 2007 - 12:06 PM Post subject: Parapit flashings
Good morning! Aaaaa yes. The flutter of beagle ears at the foot of my bed tells me its time to start another day in the fabulous life of the friendly air conditioning man. Wrong! Those ears mean only one thing. Feed me dumb human. Now the reason I’m here. Need your take on something boys. Now that I found the flashing material for the parapit (I didn’t know that modern technology could get aluminum that thin) on my new house I have to install it. Now for some of you your saying, so. Easy if you’ve done it before. The real question here is the corners. I was just going to cut at a 45 degree angle and over lap them with some kind of space age mastic. Anyone here got a better way of doing this? Thanks, Bobdanski0224 - Oct 06, 2007 - 06:49 PM Post subject:
What you describe is accepted practice. I would want as much overlap as possible (the angles will dictate what you can do well) and good dry fitment. I would avoid exposed fasteners (screws, rivets, nails) at all costs.
If you use a good polyurethane (not silicone) sealant like NP1, the job should last as long as your roof.coppermanandson - Oct 07, 2007 - 12:07 PM Post subject:
Thin aluminum is not good for any roof application. If long pieces are used expansion will rip it apart. Because it expands so much any flashing caulk or sealant will separate. I use .032 sheet alum. in no more then 8 ft. pcs. I 'm not sure what your trying to do but if you post a picture of the area I will help you out.BobLuland - Oct 08, 2007 - 12:33 AM Post subject:
First off the only way you can get ebony flashing is in aluminum. Below find my fine piece of artistry. I have the screws with the rubber washer which I intend on painting black and installing on the sides to prevent the wind from getting up under it. I’m located right off the Hudson river and the winter wind is unforgiving. I’m keeping the lengths to eight feet do to the fact that’s the size of my brake. The drip leg will be a ½” hem. Thanks for your combined efforts. Bob.danski0224 - Oct 08, 2007 - 11:18 AM Post subject:
Ebony as in black?
That should be available in just about any material from steel sheet to aluminum, in common stock sizes like 24" coils and 4'x8' or 5' x 10' sheets.
Local big box stores here have .019" aluminum coil stock on the shelf in black, local siding/building supply shops have it in .029" and .024" coils. Standard coils are 24" wide x 100' long with some material available in 8" and 12" coils. Bigger siding supply shops can slit your material to width and rewind (coil) it for a fee.
Painted steel and aluminum sheet should be available from almost any metal supplier.
You should be able to call up almost any big architectural sheet metal shop and have the pieces made to your specs. The bigger shops should have black material on hand, which will be cheaper than getting a few sheets special order.MattM - Nov 13, 2007 - 03:09 AM Post subject:
Use a cap with a cleat. The drip edge on one side will lock over your cleat. Put the same kink out on the cleat as your face and they will match up fine. This will leave a pretty face on the outside face and the screws only show on the backside.MattM - Nov 13, 2007 - 03:24 AM Post subject:
Oh, for the installing try this little diagram I whipped up.
I like to begin the mitre on a cap metal with a 1" tab on the end of the first piece laid in and then finish with a 1/4" tab over the corner face to help hold them together and hide the seam. This way you can always later use small metal zip screws painted to the same finish color if you would need them. A good pressure fitted joint shouldn't need the screws on the face. But with black its really not very visible if you do add them later.rothalion - Nov 13, 2007 - 03:33 AM Post subject:
MattM is correct but use a large cleat reciver if you have wind concerns. Say 1" and .75" behind. I can't make a picture. Also screws instead of nails might be prefered with wind issues for fastening your cleat and back side of coping. Also how do you plan on dealing with the laps between your eight foot sections?MattM - Nov 13, 2007 - 01:04 PM Post subject:
I would expect him to use a notch on the face of the underlying piece. The notch should include the tip of the hem so that there is room for the overlaid piece to lock onto it. You would treat a lap notch as cleat material and hook over both the notch and cleat at the same time. If you leave the edge of the hem it will bow the face of the overlain cap material, so get a good healthy notch cut.