# Rerouting water pipes inside a wall between townhouses



## Byn (Oct 7, 2020)

Hi all,

I had a water pipe burst in/below my slab foundation in my townhome/quadplex. For several reasons, we want to reroute the pipes inside. The wall to route the pipes to the kitchen is a shared wall with my neighboring townhouse. Every plumber through say it’s not an issue, but the debate is whether the pipes can be between the Sheetrock and the dividing wall. Some state the pipes must run inside the home on the surface of the Sheetrock and can be covered by decorative shelving, etc. Others state it can be run behind the Sheetrock between the walls. My bathroom plumbing DOES run between the Sheetrock and the concrete separation, but those pipes are original (as far as I know) to the 1974 construction. Can the pipes be run behind the Sheetrock? Or should I be dropping those plumbers/contractors from consideration? 

Thanks,
Byn


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## cda (Oct 7, 2020)

Do each of you own the townhome you are in?

There maybe a rated wall separating the units, if there is different rules apply.

The best advice is

Ask the city Building Offical
Whoever does the work, have them get a permit First, Give you a copy of it,

Do not pay them till the City inspects the work.

1974 codes may be a little different


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## steveray (Oct 7, 2020)

Most likely a fire rated wall between the units so it would take some research to see whether the plumbing is allowed or not...


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## classicT (Oct 7, 2020)

Townhome separation walls have been built many different ways over the decades. Would need to know what the cross-section of the wall looks like to make a definitive answer. 

Until then, it is a maybe.


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## classicT (Oct 7, 2020)

This is the current code for Maryland....

*R302.2 Townhouses*
Walls separating townhouse units shall be constructed in accordance with Section R302.2.1 or R302.2.2.

*R302.2.1 Double Walls*
Each townhouse shall be separated by two 1-hour fire-resistance-rated wall assemblies tested in accordance with ASTM E119, UL 263 or Section 703.3 of the _International Building Code._

*R302.2.2 Common Walls*
Common walls separating townhouses shall be assigned a fire-resistance rating in accordance with Item 1 or 2. The common wall shared by two townhouses shall be constructed without plumbing or mechanical equipment, ducts or vents in the cavity of the common wall. The wall shall be rated for fire exposure from both sides and shall extend to and be tight against exterior walls and the underside of the roof sheathing. Electrical installations shall be in accordance with Chapters 34 through 43. Penetrations of the membrane of common walls for electrical outlet boxes shall be in accordance with Section R302.4.

Where a fire sprinkler system in accordance with Section P2904 is provided, the common wall shall be not less than a 1-hour fire-resistance-rated wall assembly tested in accordance with ASTM E119, UL 263 or Section 703.3 of the _International Building Code_.
Where a fire sprinkler system in accordance with Section P2904 is not provided, the common wall shall be not less than a 2-hour fire-resistance-rated wall assembly tested in accordance with ASTM E119, UL 263 or Section 703.3 of the _International Building Code_.


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## Paul Sweet (Oct 7, 2020)

Many building officials will allow you to line the stud cavity with fire-rated drywall to maintain the fire rating.  If there's a concrete (or block) wall inside the studs that might be the fire wall.  It's best to discuss it with the building official, as CDA said.

If it was built in 1974 it was probably built under the CABO 1&2 Family Code or BOCA, and the repair would probably be subject to the International Existing Building Code.


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## north star (Oct 8, 2020)

*& # & # &*

and Welcome *** Byn *** to The Building Codes Forum !  

*& # & # &*


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## Byn (Oct 8, 2020)

cda said:


> Do each of you own the townhome you are in?
> 
> There maybe a rated wall separating the units, if there is different rules apply.
> 
> ...


I own. The neighbors rent.


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