Townhouse fire wall

[Jmeng1026]

I am working on a set of plans for a five unit townhouse building that had a fire and now needs to make some upgrades to meet code.

The units are two stories and there is a double wood stud wall separating each unit. However, the floor joists bear on the double wood stud wall and overlap each other.

Typically two layers of 5/8" type x gypsum is installed on both sides of the wall from slab to roof sheathing (with a gable truss on each side of the wall). However, in this case the floor joists are creating a problem.

The only thing I can think of is to put the double layer of gypsum on the 1st floor wall, then get the 1st floor ceiling to be fire rated and then put a double layer of gypsum on the 2nd floor wall up to the roof sheathing. Would that work?

Is there a way to do it without having to fire rate the ceiling?

Thank you for the help.

 

[jayrod12]

You'd have to have that talk with your AHJ. I believe we've had success just having the wall gypsum extend up between joists to underside of floor sheathing, and then fire caulked around the joist. But whether your local authority is willing to accept that I cannot say.

 

[JLNJ]

Talk to the architect and find out what is required at this detail. There must be a UL assembly/system which this joint is detailed for.

These multi-unit wood buildings (especially the older ones) perform horribly in a fire and the AHJ is right to make sure the fire separation wall does its job.

 

[Brad805]

The architect needs to do a code review and determine if you need a fire wall or fire separation. There are fundamental differences between those terms. Once the architect has done their code review they will tell you the requirements.

 

[RWW0002]

The architect needs to do a code review and determine if you need a fire wall or fire separation.

Ha! You must mean "The architect needs to ask the structural engineer to determine if a fire wall is needed, then proceed to completely misunderstand the differences in a firewall and a fire separation until the engineer eventually gives up and just does the code research for them"..

 

[Brad805]

RWW, most of the architects I work with are good at that part. Some in our area have elected to sub it out to so called code experts. I have never understood that. The archs we deal with tend to chit the bed when it comes to making sure things fit and doing the coordination steps that used to be the norm.

 

[RWW0002]

It was a bit of a cheap shot since the architects aren't here to defend themselves. I guess we all get drug into some out of scope work or excessive coordination between design teams from time to time..

 

[milkshakelake]

Agreed that this is an issue for an architect to handle, if you have that resource available. Them providing a signed and sealed detail will take the responsibility away from you. It's supposed to be their bread and butter. If they misunderstand the issue, it's still not your fault. Plus, how could you be expected to resolve it when it's what they do every day and can still make a mistake?