DBearss

Townhouse demising wall

Recommended Posts

Am trying my first townhouse project and am curious as to the best way to create the double wall between units. Typically the wall would be two 2x6 walls with 1" airspace between. Do I create a wall type with all the elements or just draw 2 walls next to each other?

thanks.

Share this post


Link to post
Share on other sites

Am trying my first townhouse project and am curious as to the best way to create the double wall between units. Typically the wall would be two 2x6 walls with 1" airspace between. Do I create a wall type with all the elements or just draw 2 walls next to each other?

thanks.

Hmmmmm, not having done it, I would think 2 sepate 2x4 walls. I think 2 sepate walls would give more control.

Share this post


Link to post
Share on other sites

I have done a few and always used 2 walls. You have to show the fire stops and double truss with drywall or extended walls to split the attic space. It works fairly simple and the sections look right.

Share this post


Link to post
Share on other sites

For the firewall I use a product called shaft wall along with 2x4 walls on each side the shaft wall which meets the fire separation fire code and the guys around here love it

Share this post


Link to post
Share on other sites

Ray,

 

I often have a problem with such walls from the standpoint of the fire separation at the floor/ceiling/attic where it should actually go all the way from foundation thru the roof.  Most codes allow the fire separation at the roof to be substituted by extending it 2-4 feet perpendicular to the wall.

 

How do you handle the floor platforms with both fire, sound and structural requirements?  It's easy to detail something that appears to do the job but not so easy to actually build it.

Share this post


Link to post
Share on other sites

Joe the floor platforms are handled as separate area with the shaft wall being continuous from the foundation wall up to under the roof sheathing, we do full foundations here so the foundation wall be it 10” poured conc. Then the shaft wall starts on top of that, when having a basement beam it is usually a steel beam and has a post and footer at the separation conc. wall

Share this post


Link to post
Share on other sites

I use the already built in SIP wall by Chief and just modify the thickness of the exterior layer to represent the 2x4's and the middle concrete layer as the air space. Shows up great and behaves as it should. Just adjust thicknesses and hatch patterns.

Do not use two wall. You will regret it. Plays havoc with everything else.

Share this post


Link to post
Share on other sites

Joe the floor platforms are handled as separate area with the shaft wall being continuous from the foundation wall up to under the roof sheathing, we do full foundations here so the foundation wall be it 10” poured conc. Then the shaft wall starts on top of that, when having a basement beam it is usually a steel beam and has a post and footer at the separation conc. wall

So really, the best way to model this would be (3) walls with "open below" for the air space room between the fire (shaft) wall and the structural walls. 

To actually build it the contractor would have to start at one end of the building and progress building framing walls, shaft wall, framing wall --- framing wall, shaft wall, framing wall --- .......

Share this post


Link to post
Share on other sites

So really, the best way to model this would be (3) walls with "open below" for the air space room between the fire (shaft) wall and the structural walls.

To actually build it the contractor would have to start at one end of the building and progress building framing walls, shaft wall, framing wall --- framing wall, shaft wall, framing wall --- .......

Share this post


Link to post
Share on other sites

Joe yes that is the way they do it frame one unit add shaft wall then frame the next unit shaft wall again and continue on, this way the inspectors consider them to be all separate units

Share this post


Link to post
Share on other sites

http://www.usgdesignstudio.com/

 

Use this to design a wall. This will give you UL and GA fire wall standards. Here, it is required to have Type "X" drywall attached to the roof sheathing 24" out from the demising wall each side.

Jim looking at your example using only one studded wall doesn't let and room for any electrical or hvac items in those walls, with doing the double studs with the shaft wall between let the builder put these there without compromising the integrity of the fire wall

Share this post


Link to post
Share on other sites

The Electrician knows the requirements for fire walls and deals with that. Most of my work is commercial and the Electrical plans have to be reviewed by the Fire Marshal.  

Share this post


Link to post
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now

  • Member Statistics

    27468
    Total Members
    6254
    Most Online
    gbattaglia
    Newest Member
    gbattaglia
    Joined