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-   -   basement framing (http://www.diychatroom.com/f19/basement-framing-161946/)

greencat 11-02-2012 11:57 AM

basement framing
 
Hi I am helping a friend finish his basement. I have done it for myself but since I am helping him I want to make sure everything is done correctly.

Question : someone told me that we need a piece of drywall as a spacer between the top plate and the rafters. Is that correct?

joecaption 11-02-2012 12:00 PM

Why would you do that?

mae-ling 11-02-2012 12:01 PM

ON the interior walls we would leave them down 1/2" so if the floor in the basement heaved it would have room to move before effecting the upstairs joists.
We used 1/2" pieces or plywood as temporary shims that we pulled out after nailing the top plate to the joists.
Did this when using drop ceiling in basement.
Different method for drywalled ceiling.

Gary in WA 11-02-2012 11:35 PM

Welcome to the forums!

Perhaps you are thinking of the drywall as fire-stopping to the above floor/ceiling joists...

Gary

greencat 11-03-2012 05:46 PM

Hi Gary
You are correct. He thinks it is required as a fire stop. Don't know where he got that idea.

Gary in WA 11-03-2012 11:06 PM

Probably from the building codes since at least '73 since I started framing. Fire-stop in wall at cove ceiling also. Here is the current code; "1. In concealed spaces of stud walls and partitions, including furred spaces and parallel rows of studs or staggered studs; as follows: 1.1. Vertically at the ceiling and floor levels. 1.2. Horizontally at intervals not exceeding 10 feet (3048 mm)."From: http://publicecodes.cyberregs.com/ic...002_par017.htm

Acceptable materials- - 1/2" gypsum board, etc.; http://publicecodes.cyberregs.com/ic...002_par018.htm

An outlet fire could travel across the wall or up into the floor/ceiling joist cavity above and follow a plumbing pipe/wiring hole (on other side/end of house) to surface in the attic, burning the house down from above and up from below.

Post #8, 21, and #22: http://www.diychatroom.com/f98/how-f...-37190/index2/

Gary


hand drive 11-04-2012 09:58 AM

Quote:

Originally Posted by greencat (Post 1044028)
Hi Gary
You are correct. He thinks it is required as a fire stop. Don't know where he got that idea.


wood and firecaulking/foam is used best as a firestop. drywall is to crumbly...

greencat 11-04-2012 02:42 PM

Is it to fill in any gaps between the top plate and the floor joists? Do I need this only where an outlet is or along the entire wall? I want to thank everyone for their help.

hand drive 11-04-2012 03:08 PM

Quote:

Originally Posted by greencat (Post 1044669)
Is it to fill in any gaps between the top plate and the floor joists? Do I need this only where an outlet is or along the entire wall? I want to thank everyone for their help.

firestop behind the top wall plate is most efficient, at the underside of the top wall plate where it is close to the foundation wall to be exact. On basement walls that average 1/2" away from the concrete foundation wall I fireblock in the stud bays to the underside of top plate and fire foam the 1 1/2" slots where the studs are. I do this to walls that are already built, if I'm building it from scratch then the fireblock is worked out above the top plate at the underside of the joists before the wall is built... it is to stop air from flowing behind the wall up into the joist cavities above

or, just fire foam behind the entire wall at the plate, I'm a carpenter and love wood so the way explained above is how I* do it

Gary in WA 11-04-2012 04:44 PM

Quote:

Originally Posted by greencat (Post 1044669)
Is it to fill in any gaps between the top plate and the floor joists? Do I need this only where an outlet is or along the entire wall? I want to thank everyone for their help.

-----Along the entire wall, between the new top plate and any existing house framing (mud sill plate). Also, minimum code requires fire-stopping every 10' horizontally in your new stud wall- to the concrete block/poured wall. You can use any wood other than p.t. if a vapor barrier/retarder foam sill sealer or poly plastic is used;
"7. Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapor retarder is applied between the wall and the furring strips or framing members." From: http://publicecodes.cyberregs.com/ic...9_3_sec017.htm

Use a sill sealer foam product under the bottom plate to limit the air/thermal/capillary conducting there; http://www.greenbuildingadvisor.com/...-building-code

Rigid foamboard glued (air-tight) to the concrete is the safest way to control below/above grade moisture problems in a basement; http://www.buildingscience.com/docum...study-analysis

Gary

greencat 11-05-2012 06:38 AM

1 last question. Does fiberglass batting insulation count as fire block

hand drive 11-05-2012 08:49 AM

Quote:

Originally Posted by greencat (Post 1045069)
1 last question. Does fiberglass batting insulation count as fire block


No, rockwoool works up to one half inch in my area but a can of fire foam is the ticket and seals best,one can is from 10$ to 15$. avoid getting the fire caulking unless you only have holes to fill...

Gary in WA 11-05-2012 10:47 PM

Yes, if under the IRC: "Batts or blankets of mineral wool or glass fiber or other approved materials installed in such a manner as to be securely retained in place shall be permitted as an acceptable fire block. Batts or blankets of mineral or glass fiber or other approved nonrigid materials shall be permitted for compliance with the 10 foot horizontal fireblocking in walls constructed using parallel rows of studs or staggered studs." From post #6, above: http://publicecodes.cyberregs.com/ic...002_par018.htm

"
R602.8.1.1 Unfaced fiberglass.

Unfaced fiberglass batt insulation used as fireblocking shall fill the entire cross section of the wall cavity to a minimum height of 16 inches (406 mm) measured vertically. When piping, conduit or similar obstructions are encountered, the insulation shall be packed tightly around the obstruction." From: http://publicecodes.cyberregs.com/ic...002_par019.htm

Though, I wouldn't use it for that, they are like oxygen pumps; http://www.cellulose.org/userdocs/TechnicalSpecifications/ConsumerUpdate02-InsulationEffectiveness.pdf

Gary
P.S. Where are you located?


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