Construction forum - Fastening down Wonderboard to floor joists

Author

Fastening down Wonderboard to floor joists

Sammy bin Snoozin

2007-10-20, 1:25 pm

What's the best way to do this? Below is from Eric Gurney 7/21/2000 =
which is the best I could find with google...

From =
http://www.custombuildingproducts.c...rBoard12.htm=20
(link no longer good)

Fasteners: Galvanized roofing nails, 1 1/2" (38 mm) long with hot-dipped =

galvanized coating for use with wood framing. Nails should meet Federal=20
Specification #FF-N105B/type 2 style 20. Custom Concrete Backerboard =
Screws=20
or equivalent, 1 1/4" (32 mm) long, for use with wood or 20 gauge steel=20
framing.=20

Underlayment: Using a 1/4" (6 mm) square-notched trowel, apply a setting =
bed=20
of latex-modified mortar to the subfloor or base. Immediately laminate =
1/2"=20
WonderBoard Concrete Backerboard to subfloor base, leaving a 1/8" - =
3/16"
(3 - 5 mm) space between boards at all joints and corners. Stagger =
joints so=20
they do not line up with underlying substrate joints. Fasten backerboard =

every 6" - 8" (15.2 - 20.3 cm) o.c. throughout board field and around =
all=20
edges while setting bed mortar is still workable. Around perimeter of =
each=20
board, locate fasteners within 1/2" - 2" (1.2 - 5.1 cm) of edge. Fill =
all=20
joints and corners solid with latex-modified mortar. Taping of floor and =

counter joints is not required.=20

Sam

Robert Allison

2007-10-20, 1:25 pm

Sammy bin Snoozin wrote:

> What's the best way to do this? Below is from Eric Gurney 7/21/2000 which is the best I could find with google...
>
> From http://www.custombuildingproducts.c...nderBoard12.htm
> (link no longer good)
>
> Fasteners: Galvanized roofing nails, 1 1/2" (38 mm) long with hot-dipped
> galvanized coating for use with wood framing. Nails should meet Federal
> Specification #FF-N105B/type 2 style 20. Custom Concrete Backerboard Screws
> or equivalent, 1 1/4" (32 mm) long, for use with wood or 20 gauge steel
> framing.
>
> Underlayment: Using a 1/4" (6 mm) square-notched trowel, apply a setting bed
> of latex-modified mortar to the subfloor or base. Immediately laminate 1/2"
> WonderBoard Concrete Backerboard to subfloor base, leaving a 1/8" - 3/16"
> (3 - 5 mm) space between boards at all joints and corners. Stagger joints so
> they do not line up with underlying substrate joints. Fasten backerboard
> every 6" - 8" (15.2 - 20.3 cm) o.c. throughout board field and around all
> edges while setting bed mortar is still workable. Around perimeter of each
> board, locate fasteners within 1/2" - 2" (1.2 - 5.1 cm) of edge. Fill all
> joints and corners solid with latex-modified mortar. Taping of floor and
> counter joints is not required.
>
> Sam

If you are trying to fasten wonderboard directly to floor
joists, then there is your problem. The reason that you can
find no instructions on how to do it, is because you cannot do
it. Wonderboard cannot bridge floor joists, so you must have
and underlayment to support it. Then you fasten the
wonderboard to the underlayment.

--
Robert Allison
Rimshot, Inc.
Georgetown, TX

Sammy bin Snoozin

2007-10-21, 1:25 pm

Ah so! Thanks. What is underlayment?

"Robert Allison" <rimshot27@spamless.net> wrote in message =
news:R7rSi.602$od4.301@trnddc04...
> Sammy bin Snoozin wrote:
>=20
which is the best I could find with google...[color=darkred]
http://www.custombuildingproducts.c...rBoard12.htm=20[color=darkred]
hot-dipped=20[color=darkred]
Federal=20[color=darkred]
Screws=20[color=darkred]
steel=20[color=darkred]
setting bed=20[color=darkred]
laminate 1/2"=20[color=darkred]
3/16"[color=darkred]
joints so=20[color=darkred]
backerboard=20[color=darkred]
around all=20[color=darkred]
of each=20[color=darkred]
Fill all=20[color=darkred]
and=20[color=darkred]
>=20
> If you are trying to fasten wonderboard directly to floor=20
> joists, then there is your problem. The reason that you can=20
> find no instructions on how to do it, is because you cannot do=20
> it. Wonderboard cannot bridge floor joists, so you must have=20
> and underlayment to support it. Then you fasten the=20
> wonderboard to the underlayment.
>=20
>=20
> --=20
> Robert Allison=20
> Rimshot, Inc.
> Georgetown, TX

Sammy bin Snoozin

2007-10-21, 1:25 pm

I meant... what kind of underlayment, how thick, etc? Makes sense, but =
adding any thickness will bring the new section higher than the rest of =
the floor.

"Sammy bin Snoozin" <SammyBinSnoozin@REyahooMOVE.com> wrote in message =
news:4BLSi.1500$uE4.723@trnddc07...
Ah so! Thanks. What is underlayment?

"Robert Allison" <rimshot27@spamless.net> wrote in message =
news:R7rSi.602$od4.301@trnddc04...
> Sammy bin Snoozin wrote:
>=20
which is the best I could find with google...[color=darkred]
http://www.custombuildingproducts.c...rBoard12.htm=20[color=darkred]
hot-dipped=20[color=darkred]
Federal=20[color=darkred]
Screws=20[color=darkred]
steel=20[color=darkred]
setting bed=20[color=darkred]
laminate 1/2"=20[color=darkred]
3/16"[color=darkred]
joints so=20[color=darkred]
backerboard=20[color=darkred]
around all=20[color=darkred]
of each=20[color=darkred]
Fill all=20[color=darkred]
and=20[color=darkred]
>=20
> If you are trying to fasten wonderboard directly to floor=20
> joists, then there is your problem. The reason that you can=20
> find no instructions on how to do it, is because you cannot do=20
> it. Wonderboard cannot bridge floor joists, so you must have=20
> and underlayment to support it. Then you fasten the=20
> wonderboard to the underlayment.
>=20
>=20
> --=20
> Robert Allison=20
> Rimshot, Inc.
> Georgetown, TX

Robert Allison

2007-10-21, 5:25 pm

Sammy bin Snoozin wrote:
> I meant... what kind of underlayment, how thick, etc? Makes sense, but adding any thickness will bring the new section higher than the rest of the floor.

Please don't top post.

Underlayment thickness is determined by what you intend to put
on it, spacing of the floor joists and material used for
underlayment, including how it is installed.

> "Sammy bin Snoozin" <SammyBinSnoozin@REyahooMOVE.com> wrote in message news:4BLSi.1500$uE4.723@trnddc07...
> Ah so! Thanks. What is underlayment?
>
> "Robert Allison" <rimshot27@spamless.net> wrote in message news:R7rSi.602$od4.301@trnddc04...
>
>
>

--
Robert Allison
Rimshot, Inc.
Georgetown, TX

Sammy bin Snoozin

2007-10-22, 1:25 pm

I see. My building vocabulary is not that good. It already has 2x6 =
boards on the joists, if that's what underlayment is. They are in good =
shape.

"Robert Allison" <rimshot27@spamless.net> wrote in message =
news:eKNSi.2223$vw2.268@trnddc01...
> Sammy bin Snoozin wrote:
but adding any thickness will bring the new section higher than the rest =
of the floor.[color=darkred]
>=20
> Please don't top post.
>=20
> Underlayment thickness is determined by what you intend to put=20
> on it, spacing of the floor joists and material used for=20
> underlayment, including how it is installed.
>=20
message news:4BLSi.1500$uE4.723@trnddc07...[color=darkred]
news:R7rSi.602$od4.301@trnddc04...[color=darkred]
7/21/2000 which is the best I could find with google...[color=darkred]
http://www.custombuildingproducts.c...rBoard12.htm=20[color=darkred]
hot-dipped=20[color=darkred]
Federal=20[color=darkred]
Backerboard Screws=20[color=darkred]
steel=20[color=darkred]
setting bed=20[color=darkred]
laminate 1/2"=20[color=darkred]
3/16"[color=darkred]
joints so=20[color=darkred]
backerboard=20[color=darkred]
around all=20[color=darkred]
of each=20[color=darkred]
Fill all=20[color=darkred]
floor and=20[color=darkred]
>=20
>=20
> --=20
> Robert Allison=20
> Rimshot, Inc.
> Georgetown, TX

RicodJour

2007-11-25, 1:25 pm

On Oct 22, 10:46 am, "Sammy bin Snoozin"
<SammyBinSnoo...@REyahooMOVE.com> wrote:
>
> I see. My building vocabulary is not that good. It already has 2x6 boards on the joists, if that's what underlayment is. They are in good shape.

If you do not understand the terminology you will have a tougher time
asking questions and deciphering what is meant by the answers. Google
'construction glossary' and you'll find a good place to start to fill
in the blanks.

Underlayment is a plywood (or approved equal) layer on top of the
subfloor. In a typical tiling situation the house might have 3/4"
plywood or OSB as the subfloor. The underlayment is meant to smooth
out the surface in preparation for the tile. If your subfloor is
strong enough you don't need an additional underlayment - you can bond
the cement board directly to the subfloor.

I don't understand how you could have 2x6s as a subfloor unless your
joists are spaced far greater than the typical 16". Tile
installations live and die by how much the floor will deflect under
load. If you subfloor or joist spacing is unusual the normal advice
doesn't apply.

Post pictures on one of the free hosting sites and link to them in
your next post.

R

Sammy bin Snoozin

2007-11-27, 3:25 am

"RicodJour" <ricodjour@worldemail.com> wrote in message
news:ccd2beb3-0780-4125-a8a0-4ccccc6fec1c@i12g2000prf.googlegroups.com...
> On Oct 22, 10:46 am, "Sammy bin Snoozin"
> <SammyBinSnoo...@REyahooMOVE.com> wrote:
already has 2x6 boards on the joists, if that's what
underlayment is. They are in good shape.[color=darkred]
>
> If you do not understand the terminology you will have a
tougher time
> asking questions and deciphering what is meant by the
answers. Google
> 'construction glossary' and you'll find a good place to
start to fill
> in the blanks.
>
> Underlayment is a plywood (or approved equal) layer on top
of the
> subfloor. In a typical tiling situation the house might
have 3/4"
> plywood or OSB as the subfloor. The underlayment is meant
to smooth
> out the surface in preparation for the tile. If your
subfloor is
> strong enough you don't need an additional underlayment -
you can bond
> the cement board directly to the subfloor.

Well, thanks....it's been a month since I posted the
question. Since then I learned some of the terms, already
installed the cement board - like you say, directly to the
subfloor. (I'm not laying tile, by the way).

> I don't understand how you could have 2x6s as a subfloor
unless your
> joists are spaced far greater than the typical 16". Tile
> installations live and die by how much the floor will
deflect under
> load. If you subfloor or joist spacing is unusual the
normal advice
> doesn't apply.

Too late -- the floor's already fixed, but they were
tongue-in-groove 2x6's. From what I gather, it's std 1961
tract home construction. Again, no tile invovled.

> Post pictures on one of the free hosting sites and link to
them in
> your next post.
>
> R

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