2 Storey Deck On Top Of Flat Roof

woodworkbykirk

ive been asked to replace a rooftop deck which has 2 levels to it, currently the old deck has the posts set down into the roof and is poorly flashed which is obviously leaking, luckily its only a porch roof

with replacing this deck what would be my best method of resetting the posts so that i dont have to worry about any penetration points to flash and seal

my current thought is to set a 2x8 beam on directly on top of the flat roof over the beam which supports the rafter ends, then post up from there to support the 2nd level of deck but if i go about this method how do deflect the rain, snow and ice that will collect. where the beam is fully bearing would notching it every 16" create centered between joists create any issue.

rough dimensions are 7' x 26', then the 2nd storey is 7' x 14'

rbsremodeling

What are the house walls made of??

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woodworkbykirk

judging by the house, im guessing its balloon framed, it has cedar shingles for siding. the porch roof looks like it is possibly plywood but cant say, all ive done is look at it without opening anything up

if i go over top the flat roof with a new beam ill patch the old penetration points with ice and water + tar to seal em up

dlcj

the 2x8 idea will work if you notch out most of the material between the rafters it bears on. maybe go to a double 2x10 or 12 and make the notch 2-3 inches high and leave only about 2 inches to bear over the rafters. You will still have leaves, ice and such build up there and will need to be tared and sealed good anyway so i would just set new post directly on the beam below like it was and flash them right. You could use 2" steal pipe for post and the rubber boots made for vent pipes to flash them and cap the tops. That way no worries about water penatrating and wicking down a wood post.
Is there no way to put the post outside the pourch all the way to ground and run a beam across? May cost more i know.
Just a couple of my ideas.

Robert H. Dougl

I did a job like this some time ago at first I sad right on a rubber roof without a permit well about a year later here come the inspector had to take it down and rebuild it had run a 6x17 beam from brick wall to brick wall in your case it would be exterior wall to exterior wall depending on the hight of walls you may have to use 6x6 to come up and they will need a special hanger look in simsons strong tiles the beam I used was suppose to be treated it wasn't so I wrapped it and it worked out because one was there dosn't mean that it was done to code regards Rob

TaitINC

what type of roofing material is covering the roof currently? I use a couple different methods depending on the roofing material. I would try to stay away from laying anything on the roof. The is just going to wearout the roof in the points it touchs. no matter how you notch it, debris will still gather behind it. if you decide to lay something on the roof be sure you make some sort of access panels to clear out the debris.

spencer