A small deck that is fairly fireproof.

Started by Dave Sparks, February 26, 2019, 04:25:36 PM

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Dave Sparks

I am starting a small deck that I want to be fire safe. I do not want to use metal as this will be near sleeping rooms and I already have a metal roof that makes plenty of noise in the rain.

I was thinking of  a fireproofing coating I could roll onto wood. The other way would be to use fibrous cement on top of the underlayment.

Any good ideas would be appreciated.
"we go where the power lines don't"

MountainDon

A framework of https://en.wikipedia.org/wiki/Weathering_steel. No need to paint it at all. Plus concrete; blocks, bricks, poured, or precast and prestressed floor panels.  I don't know what the costs would be but a fire wouldn't do much to it.
Just because something has been done and has not failed, doesn't mean it is good design.


Dave Sparks

Thanks Don, Interesting but I do not want to hear the sound of rain on it below me as I already get the metal roof sound above me :(
I probably will just build with sticks and plywood and put a lay of fibrous cement on top. The deck will not really be walked on and is a way to get solar hot water panels in a better location that can drain back below for cold season.
"we go where the power lines don't"

MountainDon

Just because something has been done and has not failed, doesn't mean it is good design.

DaveOrr

Sigmadek
Aluminum frame with porcelain deck boards.
All you need is $$$$$.   :)

https://www.sigmadek.com/
Dave's Arctic Cabin: www.anglersparadise.ca


Don_P

More often than not decks ignite from below, debris and blowing embers. Heavy timber? it actually performs better in fire than unprotected metals. Spancrete and sonotube? Just throwing ideas around.

Dave Sparks

Quote from: Don_P on February 28, 2019, 06:24:22 AM
More often than not decks ignite from below, debris and blowing embers. Heavy timber? it actually performs better in fire than unprotected metals. Spancrete and sonotube? Just throwing ideas around.

Yes this is very true in the fires we have had go through here. One of the fireman said the plastic decks that are a composite are the thing he fears the most. A regular Redwood deck is fine as long as what you said is true about underneath.
"we go where the power lines don't"

jeepj667

In order to meet Wildland Fire code my deck had to be made with heavy timber structure and 2x decking.

Don_P

Your firefighter friend echoes my concerns. We were taking a break on a new plastic deck we had built. I had tried burning a cutoff and it was excellent fuel. So there we are sitting in front of the designated egress on a moat of fuel between the structure and escape, not sure I understand how that gets passed.


Dave Sparks

Where are you Don? We have been 2X or larger out here in California for a long time.

One deck has 2X and plywood underneath (to keep area underneath dry) that I plan to remove and go to metal if I lose my fire insurance. We have lost insurance 3 out of the last 10 years due to cost. On the years we lose it, I just use the money to harden something else or buy another pump. We can have 3 pump failures and still have spare :P

Do you guys think there is a way to safely secure a 3 x 5 piece of fiber cement under a deck to keep the area dry?
"we go where the power lines don't"

Dave Sparks

Quote from: jeepj667 on February 28, 2019, 01:45:49 PM
In order to meet Wildland Fire code my deck had to be made with heavy timber structure and 2x decking.

Where are ya please?
"we go where the power lines don't"

NathanS

Just curious, a raised slab is definitely out of the question?

I am pretty sure the cement board will not last very long on it's side outdoors. It is not rated for that anyway.

Don_P

Dave, I'm in the Blue Ridge in VA.

I was meaning the technical definition of heavy timber, 5x and thicker framing members.

If you put metal roofing canted under the framing that would drain moisture from above, then if you want fiber cement under that use 4x8 sheets of hardie flat panel or they make a soffit panel meant for horizontal applications up to 2'x12' long.

Dave Sparks

Where are you getting the horizontal part Don? The existing deck is 2 x6 framing with redwood 2 x 6 deck on vertical 4 x 6 poles in cement.
I have underneath plywood to keep my cats dry and the door area dry. I can easily mount metal under there to do the same thing.

I was wondering instead how I would use hardie board and safely mount it 9 feet above where people and cats walk? A frame I guess???

Maybe the metal is best as I can use it to collect more rain ::)  Beautiful area Blue Ridge!
"we go where the power lines don't"


DaveOrr

Dave, just screw the cement/Hardie board on like you would drywall inside.
Screws on 12" spacing will hold up fine.
Dave's Arctic Cabin: www.anglersparadise.ca

JRR

#15
Wouldn't vertical metal flashing attached to sides of wooden members add some fire retardant?   If sides and tops of beams/joists were covered in flashing or foil before decking added, there would be resistance to rain and fire added... I would think.   Especially if the side metal were extended low enough to form "drip legs".  ??

Dave Sparks

I am thinking on both of the replies. It sometimes is better to sleep on it :P
"we go where the power lines don't"

Dave Sparks

Quote from: DaveOrr on March 05, 2019, 10:42:32 PM
Dave, just screw the cement/Hardie board on like you would drywall inside.
Screws on 12" spacing will hold up fine.

I want to do this! The thought of that weight (underside of a deck falling on me) and then the inevitable cracking and water leaks down on my winter firewood storage and cat homes makes met want to go with a light metal corrugated. Probably needs to cover 20 feet x 4 feet so (2) 10 foot lengths and be sloped a 1/4" per foot to drain out the end.

Any different  ideas  are welcome as this is a summer project. Thx!
"we go where the power lines don't"

glenn kangiser

Dave, I'm thinking of doing some stucco in various places. You could use your corrugated overhead to keep your wood dry and get the water to a drain on one side. Vertical stucco walls around the perimeter are pretty fireproof as well as cheap if you do your own. We have a deck on our rental that is a firetrap.

I have used the burlap and cement (like stucco- CBRI medium duty concrete floor) around the old pool and I think it would work as a deck cover with added Fibermesh.... Although it would not be the rich man's choice, it is a low cost option. 😊
"Always work from the general to the specific." J. Raabe

Glenn's Underground Cabin  http://countryplans.com/smf/index.php?topic=151.0

Please put your area in your sig line so we can assist with location specific answers.

Dave Sparks

Thanks Glen! The corrugated metal under the redwood deck is what I am going to do, if I lose fire insurance, again...... :(
"we go where the power lines don't"


Dave Sparks

The fire insurance tripled and so adios amigo to them.

A question, would the metal roofing in the link be a problem with zero slope or flat? They say 3/12 slope?
This is for under a deck and a palapa or gazebo roof?

https://www.homedepot.com/p/Metal-Sales-8-ft-Classic-Rib-Steel-Roof-Panel-in-Ocean-Blue-2313235/204254788?MERCH=REC-_-PIPHorizontal1_rr-_-204255042-_-204254788-_-N


Thank-you!
"we go where the power lines don't"

Don_P

It won't leak at the seams on a 3/12, it might at a flatter slope, if that matters. The roll polybutyl tape in the seams will buy you some more leakproofing.

Dave Sparks

Thanks Don! I will roll the tape as the 2 cats might not like a leak ::)
"we go where the power lines don't"


Dave Sparks

This is a pix of the above metal. We used it also under the deck.  About $400 for a 12 x 18. There is Monsoonal moisture and big clouds this am. Perfect for dry lightning. Yuk just in time with the metal. The old Ondura on the right in the pix is tar based and there was oil coming out of the underside. Double Yuk!

https://photos.google.com/share/AF1QipON-ECmB6N4K2VJBLnfYXpZHah7I5ilLZnNe-RKXl0PbY_Realuivk0HwjbOEUefw/photo/AF1QipNCKboKg4xXnvwZ_Od8YWrOqv0mBFgTsV6K4LvT?key=MWNxZ3A1Umd4X2VWaDR0MXI3czE2R3haZGk2MXJn
"we go where the power lines don't"