Tectum Deck............again

I have to estimate about 20 small shingle roofs on a medical center w/ Tectum Decking. I laid over one of them a few years back. With the hook nails. Now they want them all torn off.

My thoughts are that after tearing off: What will the condition of the deck be? Will it take another nailing on? Will the one layer be OK, but the 2 layer sections shot?

I did a job about 20 years ago in NE where we installed plywood over the Tectum. Not sure how it has held up. We aren't in a position here to replace all of this stuff-- it is the ceiling too and there is no damage-- so is adding decking over it still the best solution? Last time we pre-drilled and fastened 'em down w/ plastic Olympic fasteners.

What would you do? >>>

Hunter Panels tells me that their "Cool Vent" panel MUST be mechanically attached

Just bear in mind what elcid mentions. Tectum that has suffered from water penetration is not to be trusted as a workable surface. I'm only a little fella 36lbs drippin' wet, but you wouldn't catch me standing on it. ;)

We had an existing nailer at the bottom but yes, adding one if missing and working from the bottom up is the solution.

Thanks Cris B. I think I will take that approach. Seems like a great solution.

I like that idea Chis B. We use it on regular iso, don't know why nail board would be any different. Yeah, I like that idea a lot. Olybond is what we usually use in lieu of insta-stik, but any low rise foam should work great.

Only question in my mind: How did you keep it from sliding during install? A nailer at the base, then work from the bottom up?>>>

Mike H (aka the King) is right once again about the vented deck. That is a great recommendation. In terms of attachment, about a year ago, we used Insta-Stik to attach the composite to the Tectum and it worked great! Consult with both the composite manufacturer and Tectum. Also visit www.tectum.com/tech_bulletins.html and open the "T-38" document.>>>

Bulb Tee is a real term. It's the upside-down T shaped channel that the tectum panel sits in. I don't know where the "bulb" comes from, unless it's the little bulb shaped end on the center leg.

Your tec screws would penetrate the bottom flanges of the "T"

El Cid. That tectum stuff is made near us, and it is EVERYWHERE. It is good stuff and will take quite a bit of water exposure before the adhesives fail. Not much different than a metal deck that rusts due to repetitive leaks. Blame the folks that let it leak for a long period of time, not the tectum. We get to roof buildings that have had 2 or 3 roofs installed over the years, and rarely do we find a panel that needs replaced.>>>

thans El Cid. it is a 30 yr. old building at least. Might take some digging to find out. Unless it stamped?>>>

Mike, I understand the structure fastening you are talkin' 'bout. I'll check out the spans. I never heard the term "bulb T" before. Would you elaborate please? thanks

Thanks Jed--- Chocoalate, Beer, Cheese & meat--- it's what's for dinner :laugh:>>>

Tectum decks IMHO are the worst structual decks that can be applied. It was commonly used decades ago by school boards as a cost saving mechanism, because of its weight, R value, and appearance as a ceiling. However, when hit by water from a failed roof, the wood fibers within would disintegrate. Nothing messier than looking at a deck that looked like a sinusoidal wave. Bid on one remedial job, that required plywood and toggle bolt fasteners. Recomend checking weight capacity of deck prior to start-up of project.>>>

Have fun Tom. Bring us back some chocolate.>>>

Twill, I think that is a question best posed to the mfr of the nail board. That way you have a finger to point if it doesn't work.

IMHO, since most tectum is 2-3' wide, you could fasten to the bulb T's with tec screws, although those would be visible. I would feel better with it fastened to a structural element rather than into tectum, but augers provide a mighty good pull out so long as they are not over driven. Over driving can be easy to do over plywood since there are no threads in the plywood. It's a fine line between snug and spun-out.>>>

Thanks Mike. How to fasten? Pre-drill the nail board & use w/ the "coarse thread" plastic (?) fasteners again?

Switzerland O/S! We are leaving the house @ 2:30 pm for a 7 pm flight out of O'Hare. We will be home in exactly 2 weeks. How is that Kalamazoo job going? I'll catch you on the next one>>>

Twil, both will work fine. Hey, when are yuou leaving for Greece?>>>

Twill,

Since this is the acustical ceiling and structural deck, and likely since it was built when energy cost was not a real consideration, it IS TIME for a thermal upgrade.

Install a vented nail board w/3" iso.

They will see major energy savings. You will be installing a more dimensionally stable product that is less likely to warp. Installing ply over tectum allows no breathing so the ply gets extremely hot.

I would imagine that the R-18 of the new vented nail board will pay for itself inside of 15 years.

They save money over the life of system, you get a good, vented, nailable surface and a larger contract. Everyone wins.>>>