Hi gang,
I need to build a recreational deck on a newly-rebuilt
flat roof that has a 2-ply "rubber" torch-welded membrane.
The new roof is framed with 3/4" plywood screwed down
on to 2x8's, 12" o.c., and is *very* stiff.
I was originally planning on doing the following:
1. Lay 2x4 P.T. "sleepers" on the membrane, 16" o.c.
2. Screw 2x6 P.T. boards on to the sleepers perpendicularly,
using three #8x2.5" green deck screws at each "intersection".
3. Leave a "nail's width" between each decking board.
4. Wait a year, then stain the P.T. decking with an oil-based stain.
Recently, I have received several suggestions from friends and
am not sure which suggestions are good and which aren't. Here
they are:
1. Glue down the sleepers on the membrane.
2. Glue down 4" strips of 1" thick rigid foam insulation on the
membrane then glue the sleepers on to the foam.
3. Use 2x6x5/4" decking instead of 2x6 lumber.
4. Use 2x4 lumber instead of 2x6 lumber.
5. Don't leave any space between the decking boards.
6. Don't *ever* stain the P.T. boards.
7. Use cedar decking boards, not P.T.
Does anyone have any ideas regarding any or all of the above
7 suggestions? Many thanks.
"Jack Goldstein" <[email protected]> wrote in message
news:[email protected]...
> Hi gang,
>
> I need to build a recreational deck on a newly-rebuilt
> flat roof that has a 2-ply "rubber" torch-welded membrane.
> The new roof is framed with 3/4" plywood screwed down
> on to 2x8's, 12" o.c., and is *very* stiff.
>
> I was originally planning on doing the following:
>
> 1. Lay 2x4 P.T. "sleepers" on the membrane, 16" o.c.
> 2. Screw 2x6 P.T. boards on to the sleepers perpendicularly,
> using three #8x2.5" green deck screws at each "intersection".
> 3. Leave a "nail's width" between each decking board.
> 4. Wait a year, then stain the P.T. decking with an oil-based stain.
>
> Recently, I have received several suggestions from friends and
> am not sure which suggestions are good and which aren't. Here
> they are:
>
> 1. Glue down the sleepers on the membrane.
> 2. Glue down 4" strips of 1" thick rigid foam insulation on the
> membrane then glue the sleepers on to the foam.
> 3. Use 2x6x5/4" decking instead of 2x6 lumber.
> 4. Use 2x4 lumber instead of 2x6 lumber.
> 5. Don't leave any space between the decking boards.
> 6. Don't *ever* stain the P.T. boards.
> 7. Use cedar decking boards, not P.T.
>
> Does anyone have any ideas regarding any or all of the above
> 7 suggestions? Many thanks.
>
>
>
I'd recommend a slip sheet on top of the roofing - a loose piece of rubber
EDPM roofing would do the trick.
Bah! I meant to say 1 1/2" thickness.
"Wood Butcher" <[email protected]> wrote in message
news:36ENb.76960$na.42766@attbi_s04...
> 3/4" thickness is fine for 16" OC sleepers.
>
> Art
>
>Jack Goldstein" [email protected]
>Date: 01/15/2004 1:16 PM US Mountain Standard Time
>Message-id: <[email protected]>
>
>Hi gang,
>
>I need to build a recreational deck on a newly-rebuilt
>flat roof that has a 2-ply "rubber" torch-welded membrane.
>The new roof is framed with 3/4" plywood screwed down
>on to 2x8's, 12" o.c., and is *very* stiff.
>
>I was originally planning on doing the following:
>
>1. Lay 2x4 P.T. "sleepers" on the membrane, 16" o.c.
>2. Screw 2x6 P.T. boards on to the sleepers perpendicularly,
> using three #8x2.5" green deck screws at each "intersection".
>3. Leave a "nail's width" between each decking board.
>4. Wait a year, then stain the P.T. decking with an oil-based stain.
>
>Recently, I have received several suggestions from friends and
>am not sure which suggestions are good and which aren't. Here
>they are:
>
>1. Glue down the sleepers on the membrane.
>2. Glue down 4" strips of 1" thick rigid foam insulation on the
> membrane then glue the sleepers on to the foam.
>3. Use 2x6x5/4" decking instead of 2x6 lumber.
>4. Use 2x4 lumber instead of 2x6 lumber.
>5. Don't leave any space between the decking boards.
>6. Don't *ever* stain the P.T. boards.
>7. Use cedar decking boards, not P.T.
>
>Does anyone have any ideas regarding any or all of the above
>7 suggestions? Many thanks.
>
There's gotta be some fall to the roof so it will drain. If you do glue them
down somehow, remember the pitch and make sure you don't restrict free
drainage. Me, I'da rather'd 4x4 posts sistered to the joists, resting on the
sill plate(except the center posts), extended through the decking. Then roof
and flash the deck and posts. Build your new deck on the 4x4's sticking out of
the new roof. Tom
Someday, it'll all be over....
You have a better handle on things than most of your friends do.
First check with the mfgr of the membrane for their recommendations.
I wouldn't screw or nail anything to the membrane as any hole is an
invitation to a leak. Nor would I glue anything to it as things move
with temperature differences and there may be a risk of tearing the
membrane.
Consider making the entire deck of 4x4 or 4x8 sections which can
be removed for maintenance of the roof or the deck. This will allow
you to use chemical cleaners, stain, oil, whatever on the deck and
not get it on the membrane where it may cause damage.
2x4 PT sleepers on edge should be fine. Trex is better as it will
never rot. Be sure to run them in the direction of the drainage.
Don't use PT for the deck surface as any splinters could be poisonous.
Use cedar, redwood, trex or other material. Use either 2x4 or 2x6,
let your taste/style dictate. Space it for your climate (usually 1/8"
or so) for expansion and to allow rain to drain through. 3/4" thickness
is fine for 16" OC sleepers.
Art
"Jack Goldstein" <[email protected]> wrote in message
news:[email protected]...
> Hi gang,
>
> I need to build a recreational deck on a newly-rebuilt
> flat roof that has a 2-ply "rubber" torch-welded membrane.
> The new roof is framed with 3/4" plywood screwed down
> on to 2x8's, 12" o.c., and is *very* stiff.
>
> I was originally planning on doing the following:
>
> 1. Lay 2x4 P.T. "sleepers" on the membrane, 16" o.c.
> 2. Screw 2x6 P.T. boards on to the sleepers perpendicularly,
> using three #8x2.5" green deck screws at each "intersection".
> 3. Leave a "nail's width" between each decking board.
> 4. Wait a year, then stain the P.T. decking with an oil-based stain.
>
> Recently, I have received several suggestions from friends and
> am not sure which suggestions are good and which aren't. Here
> they are:
>
> 1. Glue down the sleepers on the membrane.
> 2. Glue down 4" strips of 1" thick rigid foam insulation on the
> membrane then glue the sleepers on to the foam.
> 3. Use 2x6x5/4" decking instead of 2x6 lumber.
> 4. Use 2x4 lumber instead of 2x6 lumber.
> 5. Don't leave any space between the decking boards.
> 6. Don't *ever* stain the P.T. boards.
> 7. Use cedar decking boards, not P.T.
>
> Does anyone have any ideas regarding any or all of the above
> 7 suggestions? Many thanks.
>
>
>
> 3. Leave a "nail's width" between each decking board.
This is what I've heard being recommended quite often, however,...
I did just that two years ago when I built my deck out of P.T., this past
summer some of the gaps were nearly 1/2" wide...
My sister had a contractor build her a deck early last year, they installed
the decking tight against one another, by the end of the summer the P.T.
had dried and there were some nice 1/8 to 1/4" gaps between the boards.
Consider this and how 'green' your P.T. is when you install it.
Maybe consider buying the decking several months early and let it dry &
shrink.
HTH,
Ron
> >Jack Goldstein" [email protected]
>>Date: 01/15/2004 1:16 PM US Mountain Standard Time
>>Message-id: <[email protected]>
>>
>>Hi gang,
>>
>>I need to build a recreational deck on a newly-rebuilt
>>flat roof that has a 2-ply "rubber" torch-welded membrane.
>>The new roof is framed with 3/4" plywood screwed down
>>on to 2x8's, 12" o.c., and is *very* stiff.
>>
>>I was originally planning on doing the following:
>>
>>1. Lay 2x4 P.T. "sleepers" on the membrane, 16" o.c.
>>2. Screw 2x6 P.T. boards on to the sleepers perpendicularly,
>> using three #8x2.5" green deck screws at each "intersection".
>>3. Leave a "nail's width" between each decking board.
>>4. Wait a year, then stain the P.T. decking with an oil-based stain.
>>
>>Recently, I have received several suggestions from friends and
>>am not sure which suggestions are good and which aren't. Here
>>they are:
>>
>>1. Glue down the sleepers on the membrane.
>>2. Glue down 4" strips of 1" thick rigid foam insulation on the
>> membrane then glue the sleepers on to the foam.
>>3. Use 2x6x5/4" decking instead of 2x6 lumber.
>>4. Use 2x4 lumber instead of 2x6 lumber.
>>5. Don't leave any space between the decking boards.
>>6. Don't *ever* stain the P.T. boards.
>>7. Use cedar decking boards, not P.T.
>>
>>Does anyone have any ideas regarding any or all of the above
>>7 suggestions? Many thanks.
one approach I like is to lift the deck off of the roof with risers
consisting of about 16" long black iron or galvanized nipples with a
bolt on flange at either end. make sure the ends attached to the roof
are bolted somewhere that can take the point load. bolt down the
flange, screw in the nipple and slip a roof jack over that. seal the
roof jack with the appropriate roofing mastics for your roof. screw
the other flange onto the top of the nipple and bolt your beams to
that.
this substructure has minimal restriction to the drainage of the roof.
Bridger