Hi everyone,

I am in the process of building my house in the Caribbean.  I will be using Quad-Lock for the walls and most likely Quad-Deck for the roof.  The design is two different structures, a 22' x 32' which is two bedrooms and bathroom and will have a low pitched gable roof and a 24' x 24' which is kitchen, living room, and office and will have a low pitched hip roof.

I am still a little unsure on whether I should go with the Quad-Deck or use the more traditional method of heavy duty rafters with t-111 sheathing, insulating foam and galvalume as the final surface.  I know the traditional route will be somewhat cheaper although I don't think by too much. 

My concerns with the Quad-Deck are rebar corrosion, thermal bridging, and the roof to gutter interface since collection of rainwater from the gutters into the cisterns is very important.

My concerns with traditional method are hurricanes primarily.  This is my main reason for going with Quad-Deck.  A secondary concern is the lifespan of the wood rafters and t-111.  My goal was to eliminate wood as much as possible.  This is due to the unknowns of how long the new copper based pressure treated wood will last in the tropical Caribbean environment.  Also, this copper based treatment (as opposed to the old arsenic treatment) means all hurricane ties need to be either stainless steel or isolated from the wood and all screws and nails need to be stainless- which also increases costs.

If I go with Quad-Deck I am considering using the gatorbar instead of steel rebar, although not sure how feasible this is.  Also considering using Xypex as a sealer followed with the silicone GacoRoof coating.

Alternatively, if I go with the Quad-Deck, should I consider attaching DOW R5 insulating foam on the exterior and then using an elastomeric paint to seal?  Seems like this could solve the rebar corrosion problem along with the thermal bridging problem although it adds more cost.  What would be the best hurricane-proof attachment method for insulating foam and what would be the best final coating if I went this route?

With a metal roof, the metal slightly overhangs the fascia giving you good rainwater collection into the gutters.  Since the edge of the Quad deck will be vertically plumb, I feel like the water runoff from the roof will not flow into the gutters as readily?  Am I overthinking this or are there other methods I am unaware of? 

Any input you have on Quad-Deck vs wood rafters and metal roof is greatly appreciated.  Any other suggestions on methods I have not considered are also welcome.  I have been toiling over these "what-ifs" for awhile now.  I am trying to obtain energy efficiency, hurricane resistance and minimal maintenance with my construction methods.

Thanks in advance for any suggestions you have. 

Tang,
I like your gatorbar idea. I haven't used it but I've heard good things about it. You might also consider Insuldeck (it is also made or owned by Quadlock).
Regards

Thanks Texas. Do you know what if any are the differences between Quad-Deck and Insuldeck?

Also, I should have noted that these structures will not be climate controlled but cooled through ventilation. So this may make adding extra insulation o ntop of ICF roof unnecessary.

I would look at some exterior insulation for the roof regardless.

Otherwise you have the roof thermal-bridging right into your ICF walls.

Do you really want your roof to be a giant hotplate?

Quad-Deck and insuldeck are the same thing. I used this in the U.S. to build. We also have an all concrete house in the caribean (D.R.) we did not use any insulation as there is no heating and very little cooling needed- use reflective white on the roof to keep the concrete from heating. Nobody that has the money to build with concrete uses wood to build were we are due to hurricanes and bugs- I have seen termites and ants due incredible damage and travel great lengths to reach rafters.

Thanks for your reply ksandjs.

I have to admit I am starting to rethink the need for ICF here in the Caribbean. No A/C will be used in my house, just the tradewinds to provide fresh air and cooling breezes. I never really liked the idea of foam on the inside and then the exterior foam is a possible place for damage and would need repair after a hurricane hurls things at it.

I'm still on the fence with roof type. Concrete is strong but its also expensive and would still need insulation on top and probably a metal roof for piece of mind to prevent leaks. Unlike the DR and even Puerto Rico, in the Virgin Islands wood roofs are still very popular and concrete is not seen as much. I think some of it has to do with the aesthetic of the open rafter look.

We do not use A/C , most of the time the windows are open and our location gives us a good breeze. Another advantage of the concrete roof is our house is off grid and solar panels have a way of disappearing -- installed them in such a way that concrete would have to be hammered away to get them out. And if you are ever in the house during a hurricane-- wow a metal roof can be so loud you can't sleep or think. Due to the climate often gables/ eves are not completely sealed when using rafters-- great for ventilation , but after a storm that dumps 36" of rain in 3 days with lots of wind -- that is what convinced us all concrete was the way to go.

We do not use A/C , most of the time the windows are open and our location gives us a good breeze. Another advantage of the concrete roof is our house is off grid and solar panels have a way of disappearing -- installed them in such a way that concrete would have to be hammered away to get them out. And if you are ever in the house during a hurricane-- wow a metal roof can be so loud you can't sleep or think. Due to the climate often gables/ eves are not completely sealed when using rafters-- great for ventilation , but after a storm that dumps 36" of rain in 3 days with lots of wind -- that is what convinced us all concrete was the way to go.