Author Topic: Sealing railing posts on a flat roof  (Read 196 times)

PloddingInsight

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Sealing railing posts on a flat roof
« on: August 05, 2020, 01:32:09 PM »
I have a small flat-roof balcony that is covered with asphalt roofing roll, which just started leaking.  It also has a very old and rotten-looking railing which I'd like to replace.  I'm going to remove the asphalt roll and the railing, maybe replace some of the plywood underneath if necessary, and then redo it all.  The asphalt roofing roll stuff looks pretty simple to work with, and I've done drip edge before, but I'm unsure of how to seal where the railing posts are attached.

To add: This roof will get zero actual use.  It's just a fire exit.  I wouldn't even put up a railing except that I'm worried about attracting attention from the township.

Does anybody know the process to achieve a good seal for the railing posts?

techwiz

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Re: Sealing railing posts on a flat roof
« Reply #1 on: August 05, 2020, 01:43:48 PM »
https://www.youtube.com/watch?v=vqHpdXHNTWg

Here is a video on how to do railing on a flat roof the way the professionals do it. Build it up is the key.

PloddingInsight

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Re: Sealing railing posts on a flat roof
« Reply #2 on: August 05, 2020, 01:56:24 PM »
I found that but I'm not sure what product/approach to use with asphalt roll as opposed to rubber roofing.  It looks like he glued down the wrapped post base, joining rubber to rubber.

Maybe ditch the asphalt roll and do all rubber, I guess.

techwiz

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Re: Sealing railing posts on a flat roof
« Reply #3 on: August 05, 2020, 02:15:17 PM »
I have worked with a product called "Blue Skin" before, but I am just some guy on the Internet and not a roofer.   

PloddingInsight

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Re: Sealing railing posts on a flat roof
« Reply #4 on: August 05, 2020, 02:21:58 PM »
I'd be happy to hear about it.

Here's a video with a guy who seems to have put tar down under the post's base block... and then just screwed it down.  That does seem easy!  But I don't know if I'm fully convinced that this approach will stand the test of time:

https://www.youtube.com/watch?v=mNQKaQa6VTA&t=245s


techwiz

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Re: Sealing railing posts on a flat roof
« Reply #5 on: August 05, 2020, 02:46:52 PM »
https://henry.com/commercial/self-adhered-water-resistive-air-barriers/blueskin-sa

The product sheet says it is self sealing when screwed through. So it might work and be quick and easy.  However, I would have more confidence building up the railing post and wrapping it like the first video. 

SunnyDays

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Re: Sealing railing posts on a flat roof
« Reply #6 on: August 05, 2020, 04:09:48 PM »
Flex seal?

lthenderson

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Re: Sealing railing posts on a flat roof
« Reply #7 on: August 05, 2020, 06:46:39 PM »
Here's a video with a guy who seems to have put tar down under the post's base block... and then just screwed it down.  That does seem easy!  But I don't know if I'm fully convinced that this approach will stand the test of time:

Tar that is kept from sunlight and air, i.e. inbetween the block of wood and the roof will last almost indefinitely. That is why wooden boat builders use it to seal joints between too pieces of wood to prevent water from penetrating. Probably the biggest worry about doing it that way is that over time, especially if you use treated wood right out of the store that still has a lot of moisture in it, wood will shrink and the fastener will loosen up as a result. I would definitely snug them up every six months for the first year or two. Personally, I would go with some sort of metal bracket that doesn't shrink with time or flash up and over the block as in the other video.

PloddingInsight

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Re: Sealing railing posts on a flat roof
« Reply #8 on: August 06, 2020, 06:00:49 AM »
Here's a video with a guy who seems to have put tar down under the post's base block... and then just screwed it down.  That does seem easy!  But I don't know if I'm fully convinced that this approach will stand the test of time:

Tar that is kept from sunlight and air, i.e. inbetween the block of wood and the roof will last almost indefinitely. That is why wooden boat builders use it to seal joints between too pieces of wood to prevent water from penetrating. Probably the biggest worry about doing it that way is that over time, especially if you use treated wood right out of the store that still has a lot of moisture in it, wood will shrink and the fastener will loosen up as a result. I would definitely snug them up every six months for the first year or two. Personally, I would go with some sort of metal bracket that doesn't shrink with time or flash up and over the block as in the other video.

Thank you! This is the kind of information I am after.

Just Joe

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Re: Sealing railing posts on a flat roof
« Reply #9 on: August 06, 2020, 08:52:17 AM »
Flex seal?

Hey Flexseal would have kept the Titanic afloat...