Attaching posts to a waterproof deck.

[5.4MarkVIII]

I know we have some deck pros on here.
we have, what was a covered deck off the master bedroom. Under the deck is actual basement. It’s on an outside corner. So the two railing sides are directly above cinder block walls the other two sides are walls. (If that makes sense)

The “decking” is out door carpet which appears to be glued to some sort of rubber but I have not yet pulled up any of the decking.

I did however discover that the existing rails were originally only about 2 and a half feet up. And then Apparently the PO wanted to cover it so just stuck another 4x4 post on top of the existing hand rail.

It was sketchy . So I’m re doing it. Ive done a couple decks before and helped my did with a couple as well but I have never done one on top of a waterproof surface. Just wondering what the best Method is to attach the new vertical posts to hold the roof and handrails. Currently is just a 2x4 block nailed threw the membrane and then The 4x4 post screwed to that.

Also what would the life expectancy of this water proof roof be? Never had a leak. But wondering if it’s a good idea to have it inspected or even replaced before I build a new deck on top.

It’s in really good shape being that it was a covered deck.

Thanks gents.

[Laffs]

Any photos?

Are you saying the carpet is glued to a rubber membrane or referring to the rubber backer of the outdoor carpet? What's the substrate underneath the carpet?

[5.4MarkVIII]

Any photos?

Are you saying the carpet is glued to a rubber membrane or referring to the rubber backer of the outdoor carpet? What's the substrate underneath the carpet?

I’ll get some pictures. Rubber looked to be separate from the carpet. It’s black and maybe a 1/16 the thick and then the carpet seems to be glued to it.

I’m not 100% sure of the substrate. Since it’s closed in below.

[Laffs]

I’ll get some pictures. Rubber looked to be separate from the carpet. It’s black and maybe a 1/16 the thick and then the carpet seems to be glued to it.

I’m not 100% sure of the substrate. Since it’s closed in below.

Might be EPDM Rubber which is a really good thing for you if it is. Give me 10 min I'll take a photo of some on the roll in my shop.

[5.4MarkVIII]

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deck is roughly 10 feet deep and 14 feet wide.

this next picture is how they attached the originally corner post. on closer inspection the carpet is newer than the wood structure. so im thinking they cut the posts to get the new carpet under and then blocked the posts back up again. is there a better way to fasten the posts threw the membrane or is it just screws and caulk?
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this is about all i can see of the membrane. almost looks like shingle material but seems much more pliable.
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[Laffs]

Ah fuck that looks like Mod Bit.

[Laffs]

Ok so attached are two different roofing system samples.

First one (the granulated roll) is whats called Mod Bit or Modified Bitumen. It's a base and a cap sheet normally torch applied to the substrate.

Second one is the rubber membrane called EPDM. It's normally fastened down with screws at the seams or fully adhered.

Based on the pic you send I'm guess it's Mod Bit you have up there.

[5.4MarkVIII]

what kind of life span could one expect from something like this if it was carpeted and covered from the elements?

[Laffs]

If it's Mod Bit the proper way to do this would be
-cut the roof out to the substrate
-attach the post base to the wood or concrete
-drop your 4x4 in the base
-add cant strip (45 degree angled wood blocking) to the perimeter of the post
-bring new base and cap sheet up the post a few inchs
-add 3 course mastic/mesh to the corners and granules
-apply a new metal counter flashings to where the roofing ends with a water cutoff mastic

Improper way that might work would be scrape the area, screw the post base directly overtop the mod, install the post, 3 course mastic and mesh the post base in to the roof field. Kinda ugly but "should seal"

If its EPDM its

-cut the roof out to the substrate
-attach the post base to the wood or concrete
-drop your 4x4 in the base
-clean perimeter of the penetration with weathered membrane cleaner
-prime area
-apply a prefab square pipe boot with tape, roll it in to membrane
-lap seal perimeter.

Either case, I'd probably say fuck it and lag my new railing posts in to the wood fascia of the deck, then seal the area of the old posts.

[Laffs]

what kind of life span could one expect from something like this if it was carpeted and covered from the elements?

Honestly can't say I've seen a Mod with carpet glued to it, so really operating outside the manufacturers recommendations there. Normal conditions 20-25 years is acceptable, your details where it meets the walls of the house and door will likely fail and leak first before the field.

When you go to replace it I'd recommend the newer style decorative TPO/PVC membranes. They can be glued directly to plywood, have pre made factory accessory post bases, and won't require you to put carpet or anything over top. We use Global Decking/Deck King (Pic attached, theres more finish options beyond the fake rocks or fake wood in our sample but no one ever puts the fucking samples back) for patios like this all the time, good products. Any other flat roofing system will require you to do XPS or pedestals to put any type of deck board/paver over top which will drastically raise the finished floor height and fuck with your transitions.

[hammerhead]

I would be inclined to think that whole area was once a walkout deck and that room has been added then closed in with blocks beneath —judging by the siding up against the the window frame in the corner and looks also to be a flat roof on the closed in area —unless there is some sort of flashing under the siding there is a potential for water damage around the exterior walls as mentioned —the deck area itself could have been protected with a membrane and has flashing... it raises a lot of questions. I would think there's only one way to sort it out and to look deeper if the space beneath is livable space now. I'm not an engineer but many things don't look right there.

[Laffs]

I would be inclined to think that whole area was once a walkout deck and that room has been added then closed in with blocks beneath —judging by the siding up against the the window frame in the corner and looks also to be a flat roof on the closed in area —unless there is some sort of flashing under the siding there is a potential for water damage around the exterior walls as mentioned —the deck area itself could have been protected with a membrane and has flashing... it raises a lot of questions. I would think there's only one way to sort it out and to look deeper if the space beneath is livable space now. I'm not an engineer but many things don't look right there.

Rest of the house looks to be block foundation as well, plus he said its basement under. My guess is it was designed as a walk out patio.

[5.4MarkVIII]

If it's Mod Bit the proper way to do this would be
-cut the roof out to the substrate
-attach the post base to the wood or concrete
-drop your 4x4 in the base
-add cant strip (45 degree angled wood blocking) to the perimeter of the post
-bring new base and cap sheet up the post a few inchs
-add 3 course mastic/mesh to the corners and granules
-apply a new metal counter flashings to where the roofing ends with a water cutoff mastic

Improper way that might work would be scrape the area, screw the post base directly overtop the mod, install the post, 3 course mastic and mesh the post base in to the roof field. Kinda ugly but "should seal"

If its EPDM its

-cut the roof out to the substrate
-attach the post base to the wood or concrete
-drop your 4x4 in the base
-clean perimeter of the penetration with weathered membrane cleaner
-prime area
-apply a prefab square pipe boot with tape, roll it in to membrane
-lap seal perimeter.

Either case, I'd probably say fuck it and lag my new railing posts in to the wood fascia of the deck, then seal the area of the old posts.



Thanks appreciate the input. Sounds like I might be bringing in a pro (how far do you commute? Lol)

Not super keen on messing with the membrane myself if I flood the basement. My wife will kick my ass. Lol

[Laffs]

Our service guys go as far as London/Sarnia, but to be honest to pay us to do this the way we'd want to do it to ensure no leaks would be $2,500 all day and honestly I don't think that's money well spent in this case if the age of the roof is unknown. That's a huge chunk of what could go toward a newer more proper system.

I'd strongly encourage to go through with attaching new 4x4 railings to the the rim joist for now vs playing around with that roof and trying to get it all sealed. Alternatively if you wanted to get one of those prefab aluminum railing kits and secure the post base to the existing 2x4 base, along with a heavy bead of dymonic caulking around all the joints you'd likely have no issues that way.

[5.4MarkVIII]

Our service guys go as far as London/Sarnia, but to be honest to pay us to do this the way we'd want to do it to ensure no leaks would be $2,500 all day and honestly I don't think that's money well spent in this case if the age of the roof is unknown. That's a huge chunk of what could go toward a newer more proper system.

I'd strongly encourage to go through with attaching new 4x4 railings to the the rim joist for now vs playing around with that roof and trying to get it all sealed. Alternatively if you wanted to get one of those prefab aluminum railing kits and secure the post base to the existing 2x4 base, along with a heavy bead of dymonic caulking around all the joints you'd likely have no issues that way.

my only concern with attaching to the rim joist would be the point load. our hope for the mud room and decks is to upgrade and bring in a timber frame look. and the boss wants the porch to be covered again. so we are looking at upgrading to 6x6 posts and a timber frame structure to hold the roof. similar to this but with a lower pitch on the roof

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the more i stew on it the more i think Im getting it re covered with a proper decking like you mentioned.

[Laffs]

Ya if you’re cutting it open to reframe and change structure go all the way and rip it down and do a new membrane.

[5.4MarkVIII]

She always wants to do things the expensive way. Lol.

Thanks again

[Quicksilver]

As you know, I build decks for a living. Laff's methods are pretty much the way I'd go to be safe and secure.

[5.4MarkVIII]

figured i would throw an update on this.

this was our third winter since moving here and the first winter i just ignored the snow built up on this deck.

in January one of the kids said there was water dripping in the basement. sure enough under the deck a bubble had formed in the drywall on the ceiling

last week decided it was time to open it up underneath and see how bad it was.

answer not great. the vapor barrier was holding a whole bunch of water. and the drywall and insulation directly under the deck was newer than the rest. as in looks like it was replaced probably not long before the house went on the market to hide the water leak. there was mold so i pulled all the drywall down under the deck so it could dry and be treated. also decided since there was mold that better make sure it wasn't traveling down the wall. in the 6 feet of wall I uncovered i found no mould. I did how ever find a major structure issue and more electrical problems. buried wires, hidden boxes.

so that turned into a complete gut of that side of the basement. the plumbing has issues, the electrical has issues and the structure has issues.

so how is your day going?

buried wires and boxes
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[5.4MarkVIII]

window with floor joists that aren't on anything other than the window frame

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think that is bad? it gets worse. this is the beam the supports all the floor joists under the master bedroom. it also terminated above the window. as in there is nothing under one end of the beam other than a wooden window frame
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this might explain some of the drywall cracking in the master bedroom and why that window doesn't open

[RedSN]

window with floor joists that aren't on anything other than the window frame

think that is bad? it gets worse. this is the beam the supports all the floor joists under the master bedroom.

Yikes!
Double yikes!

Currently working on a job for a client in Newmarket. Some of the framing we uncovered isn’t all that dissimilar.

[5.4MarkVIII]

I shouldn’t be surprised because I see hack jobs almost every day.

But I can’t wrap my head around this.

The one is gonna be an easy fix (I think)
The other is gonna require either moving the window or making the window smaller.

[hammerhead]

WOW !!!

[Laffs]

Load bearing windows, you pay extra for those...

[Gabe]

best not to fill up the tub in the master any more I think

[5.4MarkVIII]

Load bearing windows, you pay extra for those...

I mean. There is one stud.

I stuck a Jack post under that end of the beam. Just as a temp fix. Weird how the the window actually opens.

[5.4MarkVIII]

best not to fill up the tub in the master any more I think

Just a shower luckily. Directly above that beam is the bed. Let’s be honest it’s not putting in much work anymore. Lol.