Deck/roof coating

[mridgeelk]

This is a flat deck over a garage that has been covered with either the color coat that was applied to the stucco or an elastomeric paint. It appears that Tyvek or a similar product was applied to the sheathing first. I can't find any product that is rated for this use. Anybody know of any?

Yes, those drains are about an inch higher than the lowest point of the deck.

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[Jim Katen]

This is a flat deck over a garage that has been covered with either the color coat that was applied to the stucco or an elastomeric paint. It appears that Tyvek or a similar product was applied to the sheathing first. I can't find any product that is rated for this use. Anybody know of any?

Yes, those drains are about an inch higher than the lowest point of the deck.

There are several elastomeric deck coatings. Many of them are approved for use over living space. They break down into two general classes, water-based and solvent-based. The most common one in my areas is Gacodeck, but you might have run into Spanex, Procor, Polydeck, Dex-O-Tex, Slatex, or any number of other competing brands. These products are supposed to be recoated every few years. If they become damaged, they're easy to repair.

There are, however, two overarching concerns with them. They absolutely, positively must have 1/4" per foot of slope to a drain. If water ponds on them, they will fail. Also, when you apply the original coating and when you apply subsequent coatings, the deck must be dry, dry, dry. If it's wet, the coating will fail.

[mridgeelk]

Thanks for the info, Jim. The only slope of the surface was caused by settling and what is likely an overspanned double LVL.

This is a flat deck over a garage that has been covered with either the color coat that was applied to the stucco or an elastomeric paint. It appears that Tyvek or a similar product was applied to the sheathing first. I can't find any product that is rated for this use. Anybody know of any?

Yes, those drains are about an inch higher than the lowest point of the deck.

There are several elastomeric deck coatings. Many of them are approved for use over living space. They break down into two general classes, water-based and solvent-based. The most common one in my areas is Gacodeck, but you might have run into Spanex, Procor, Polydeck, Dex-O-Tex, Slatex, or any number of other competing brands. These products are supposed to be recoated every few years. If they become damaged, they're easy to repair.

There are, however, two overarching concerns with them. They absolutely, positively must have 1/4" per foot of slope to a drain. If water ponds on them, they will fail. Also, when you apply the original coating and when you apply subsequent coatings, the deck must be dry, dry, dry. If it's wet, the coating will fail.

[hausdok]

Hi,

Jim has it absolutely correct. The other thing to note is that, if you're seeing the fiberglass used to cover the transitions from the perimeter flashings to the floor beneath the material, it's probably applied too thinly.

One of the guys I mentored into this business a few years ago spent ten years installing those things.

It begins with a raw deck. They install metal wall-to-surface flashings, drip edging, drains and scuppers and then they prime the surfaces and use a fiberglass mesh and adhesive to cover the transition of these to the surface of the deck. After that material dries, they apply the first coat of urethane and allow it to cure for about 24 hours. At that point you can still make out the scrim through the surface. The next day they return and apply another layer of urethane - at that point, the scrim should no longer be visible. It's basically daubed on with a big putty knife and then trowled over the surface and allowed to settle out. At that point, the surface is about 1/16 inch thick.

They allow that to cure for 24 to 48 hours and then they return and apply another coat - a little thicker this time - allow it to cure for about four hours and then return and sprinkle fine sand over the surface.

They then allow it to cure about 48 hours and then return, sweep off the excess sand and apply one last finish coat on top of the sand. So, the process takes at least five days for a properly-applied surface and when they're done it's very durable and about 1/8-inch thick and needs to be cleaned and a new finish coat applied about every 3 to 5 years. Done properly, you shouldn't be able to see the scrim or the borders of the copings, flashings or drains - it should be one continuous smooth surface.

ONE TEAM - ONE FIGHT!!!

Mike

[mridgeelk]

Thanks, Mike, I'll pass this on to my client.

Hi,

Jim has it absolutely correct. The other thing to note is that, if you're seeing the fiberglass used to cover the transitions from the perimeter flashings to the floor beneath the material, it's probably applied too thinly.

One of the guys I mentored into this business a few years ago spent ten years installing those things.

It begins with a raw deck. They install metal wall-to-surface flashings, drip edging, drains and scuppers and then they prime the surfaces and use a fiberglass mesh and adhesive to cover the transition of these to the surface of the deck. After that material dries, they apply the first coat of urethane and allow it to cure for about 24 hours. At that point you can still make out the scrim through the surface. The next day they return and apply another layer of urethane - at that point, the scrim should no longer be visible. It's basically daubed on with a big putty knife and then trowled over the surface and allowed to settle out. At that point, the surface is about 1/16 inch thick.

They allow that to cure for 24 to 48 hours and then they return and apply another coat - a little thicker this time - allow it to cure for about four hours and then return and sprinkle fine sand over the surface.

They then allow it to cure about 48 hours and then return, sweep off the excess sand and apply one last finish coat on top of the sand. So, the process takes at least five days for a properly-applied surface and when they're done it's very durable and about 1/8-inch thick and needs to be cleaned and a new finish coat applied about every 3 to 5 years. Done properly, you shouldn't be able to see the scrim or the borders of the copings, flashings or drains - it should be one continuous smooth surface.

ONE TEAM - ONE FIGHT!!!

Mike

[CHI]

Hey Mike,

What is the proper way to install 4x4 railing posts into the decking material? Tyipically I see the decking material rolled slightly up the side of the posts which I've been told is the wrong way to do it. It seems there should be metal flashing or the post should rest on a steel column support. Seems like the posts will eventually rot when integrated into the coating. Are there any pictures of a correct installation that you know of?

[hausdok]

Hi,

Non that I know of but I haven't searched for any.

this stuff is so tenacious and thick that if a post comes right up through it and the stuff is applied to it, I think that joint would be more reliable than one made from flashings.

Could be wrong though - often am.

ONE TEAM - ONE FIGHT!!!

Mike

[kurt]

There's big bunches of drawings for roof flashing details, including one's for 4x4 flashing details at the NRCA and nearly every mfg's. website.

I've never seen any of these goop membrane materials. They don't exist in Chicago. It's pretty much all mod bit, or granulated mod bit.

I still can't get my head wrapped around the idea there's a spread on goop for "decking" that works.

[hausdok]

Rob,

I've been thinking about it. I think that a 4 by 4 could be flashed on all sides the same way they flash and seal the deck/balcony-to-house joint.

1. Coat the post with primer

2. Install overlapping steel flashings around the base

3. Prime the flashings

4. Install the fiberglass scrim from the flashing onto the balcony and then from the flashing to the post. Allow to dry.

5. Featheredge the scrim and trowel on the first coat of urethane - allow a day or two to cure.

6. Apply a second coat - allow two days to cure. The flashings should be invisible by now.

7. Apply a third coat, allow to dry for a few hours and then spread sand on the walking surface - allow to cure for a couple of days.

8. Sweep off the excess sand, apply the finish coat and allow to dry at least 2 to 3 days.

9. Thoroughly prime and paint the balustrade posts.

As long as the posts above that point are kept well painted and the end grain sealed, there's no reason that this would not perform as long as needed. The stuff is as tough as a pickup bed liner and is flexible so that it can easily accommodate the different expansion/contraction rates of the deck materials, flashings and posts without failing.

'course, could be wrong; often am.

ONE TEAM - ONE FIGHT!!!

Mike

[CHI]

Thanks for the input. I had one about a year ago where the home was EIFS. A contractor came in behind me to look at the EIFS and mentioned to the new home owner that the base of these posts should have a flashing to prevent damage to the base of the post. I've looked around and couldn't find much information on how a better installation would look. I'll check out check out those websites Kurt.