Portico Roofing Questions


#1

I am looking to build a portico (6’D x 7’W)over my front entrance. It will be the type which is square to rectangular in shape with 2 columns on the outer corners supporting it and tied into the 2nd floor rim joist. It will also have a low railing around the perimeter for asthetics. My questions are as follows:

  1. I want to build a low slope roof for rain and snow runoff. I plan 1/4" for each foot of roof. What’s the normal config used for this type of structure? Sloped from front to back, peak in the middle with runoff to the sides, etc?
  2. I was thinking of using an EPDM membrane over plywood for the roofing but am concerned about some of the railing posts having to be screwed through it and causing leaks. What’s your suggestions or how is this normally done?
  3. What about gutters? I’ve seen some with and some without. Any pros/cans to either?

Thanks for your help.


#2

1. I want to build a low slope roof for rain and snow runoff. I plan 1/4" for each foot of roof. What’s the normal config used for this type of structure?

Peak in the middle with runoff to the sides

2. I was thinking of using an EPDM membrane over plywood for the roofing but am concerned about some of the railing posts having to be screwed through it and causing leaks. What’s your suggestions or how is this normally done?

If you’re DIY then I’d suggest a self stick membrane system like GAF Liberty or Certainteed Flintastic. For railing posts I usually use 'pitch pockets. Which is basically a box built into the flat roof, you set your post (or whatever) into thr box and fill the box with some kind of pourable sealant. Normally the posts will be in place and you will have to construct your box (pitch pocket) around it. You should be able to buy pitch pockets pre-made, ask your roofing supplier about it.

3. What about gutters? I’ve seen some with and some without. Any pros/cans to either?

Built in gutters are stylish but again if you’re DIY I’d skip those. Gutters help prevent erosion at the roof line and help carry water away from you’re foundation. Chances are if you live in a rainy climate or plan on having any plantings on the ground near your front door you will want gutters.


#3

By the phrase “roof line”, Tar Monkey means the drip line, i.e. where the water hits the grass / yard, etc.

Why such a low sloped roof, though? Anything with a 5:12 or better will work more efficiently for snow load & you could put on ‘real’ shingles (just don’t forget your Ice & Water shield for under shingles).

The solutions that go into pitch pockets are usually a two stage component; one large syringe with two cylinders that mix as you squeeze both sides of the syringes. Here’s a side view detail of a Pitch Pocket:

http://www.koppers.com/roofing/B15.GIF
(ignore the word “Koppers”; pretend it isn’t there)

These make much better connections to a slab vs. just using a base plate (& if you intend to use PT wood, do NOT use any galvanized nails or galv. tie plates / base plates).


#4

I guess I was shying away from pitch pockets as everything I’ve heard and read says they are a maintenance nightmare and are bound to leak over time. As this is for my own house, I don’t want to create a problem for myself. Is this the typical method for mounting a railing on a portico?
I’m going with such a low slope roof as anything with a bigger slope will be seen and ruin the aesthetic os the portico. I’ve attached a pic to give you an idea of what I am looking to build.

Thanks.http://www.roofing.com/images/topics/5535/img_1184071712.jpg


#5

“I guess I was shying away from pitch pockets as everything I’ve heard and read says they are a maintenance nightmare”

As long as they are filled correctly they work fine for me. You want to overfill them slightly so they shed water. If you underfill them and create a “bird bath” then yes, sure they will leak. Pitch pockets have been used on commercial apps for a long time. Maintenece is easy…just top off the pocket again. Your call but to me it is a simple design that has served me well.


#6

You are correct, in that pitch pockets are a maintenance item. Regardless of how much you fill up the pitch pocket, the fill material generally will tend to settle, age, crack, become disbonded from edges of pocket, etc. One thing you may want to consider if you go the pitch pocket route, is to install metal caps overtop of the pitch pockets, notched out around the penetration and caulked. This will give you the old belt-and-suspenders type of protection.

Now, my question is, do you really need the railing?


#7

Agreed with Cerberus to create a metal collar.

Thanks for posting the picture; that is definitely a ‘classic’ kind of look for a portico as opposed to a gabled entry.

Keep in mind that (for the top) any kind of low slope application will have an increased potential for water damage due to ponding (if not done correctly). Very special attention should be made for the flashing detail @ the roof to wall joint.


#8

Yes, I’ve seen that as well. Sorta like counterflashing. This would certainly keep out any driving rain and/or snow. Here’s a pic I found on how to accomplish this. I’m just wondering if there are are alternatives to pitch pockets that I haven’t heard about. Wish I could crawl up on this portico to see how they did it :wink:
So assuming I go the pitch pocket route does this seem about right?

  1. Pitch pocket with flange nailed/screwed to the plywood base.
  2. EPDM or GAF Liberty over the flanges run up the side of the pitch pocket.
  3. Railing in the pitch pocket (can you nail/screw the railing to secure it? If so, do you secure it through the pitch pocket or secure the railing to the plywood/joists below?)Fill pitch pocket. Install counterflashing over the pitch pocket and caulk between counterflashing and railing to seal.
  4. Flash back wall and roof. Probably go 8-10" high with the flashing. Bring it down into the EPDM and seal with a piece of uncured rubber over the flashing.

Thanks.http://www.roofing.com/images/topics/5535/img_1184090387.gif