View Full Version : Chimney in valley

Michael Scher
03-26-2008, 03:40 PM

I am looking for help on what to write up here.
Doesn't seem like chimney should have been installed in the valley...but it was.
Neither single side of chimney exceeds 30", but the combined width certainly does.
PS - This home is 11mos. old. Being inspected as part of builder's warranty service.


Separate question: Ideas on possible real solutions to 'fix' this.

David Banks
03-26-2008, 03:54 PM
I took this from another thread a while back. I think it was Richard Rushing or Rick Hurst. You could also do a search as I know it has been discussed before.
: There is supposed to be a 36" wide moisture barrier underlayment at all valleys, 18" to either side if installed correctly, Therefore no chimney(s), plumbing vent(s), or flue stack(s) should be placed within 18" of a valley. Penetrations to the moisture barrier may eventually leak and these areas will require further monitoring and sealant application if not relocated and installed correctly.

Michael Thomas
03-26-2008, 04:23 PM
Separate question: Ideas on possible real solutions to 'fix' this.

If you must put a chimney there, do it right to start:

Jerry McCarthy
03-26-2008, 04:30 PM
Code ref. number please. There's no doubt it's a bad location, but I'm unaware of a code restriction for doing such? (hope I'm wrong)

David Banks
03-26-2008, 04:45 PM
Code ref. number please. There's no doubt it's a bad location, but I'm unaware of a code restriction for doing such? (hope I'm wrong)

Jerry. Are you questioning the figures in the quote or that the Chimney is not allowed in a valley by code? I do not think the quote implies that there is a code prohibiting chimneys in valleys. Quote says " Therefore no chimney(s), plumbing vent(s), or flue stack(s) should be placed within 18" of a valley.
It says should not shall. Just a recommendation.
As for the figures 2003 IRC R905.2.8.2.
There may be some disagreement on these figures as I think I remember Jerry P and Richard Rushing going round and round on this issue. I could use some enlightenment myself.

Billy Stephens
03-26-2008, 06:12 PM

The trim on the Chimney Chase does not have the correct clearance from the roof.

If it's not rotten now it soon will be.

Jim Luttrall
03-26-2008, 07:44 PM
Maybe everyone should make a new section on reports entitled "Stupid Things" for things that are so stupid that there was no place for them in the code book.

Aaron Miller
03-27-2008, 04:20 AM
The chimney in question being in Texas would need to conform to TRCC performance standard 304.17(i):

(i) A pipe, vent, fireplace or other object designed to penetrate the roof shall not be located within the area of roof valley centerline without proper "cricketing" or other Code-approved water diversion methods. If a pipe, vent, fireplace or other object designed to penetrate the roof is not correctly located as provided in the performance standard stated in this subsection, the builder shall take such action as is necessary to bring the variance within the standard.

Then there's NRCA's statement on page 346 of their Roofing and Waterproofing Manual that "A clear, unobstructed drainage way is desired in valleys, so that the valley may carry water away quickly and perform successfully for the life of the roof system".

Then there is the issue of common sense, but hey, that's been long gone from the homebuilding industry.


Aaron Miller
03-27-2008, 08:21 AM
Yet another valley ornament from this morning.


Jerry McCarthy
03-27-2008, 08:34 AM
I don't recall any code addressing a fireplace chimney being located in a roof valley and took a few minutes to consult my 2006 IBC, IRC and 2007 CBC and found nothing regarding such. If such a code exists I'm unaware of it.
I just list things like what's shown under "dumb things architects and builders do."

Jerry McCarthy
03-27-2008, 08:42 AM
Here's a runner-up. :(

Daniel Stone
03-27-2008, 08:43 AM
I totally agree with Jim Luttrall...just plain stupid. What builder in this day and age...(or architect) wouldn't look at that and go...NOPE not gonna build that. I wouldn't. Looks like a mod to plans to me...owner says "I wanna change the fireplace to the other wall cause my wife doesn't like to put her feet to the right when she's watching tv.....etc. etc....
Some people will just do anything.

(** lovely touch on the dryer vent too, huh?)

However, the real answer is what can be done for Michael's clients. I very much like the idea of the diverting wall (cricket) to make dual valleys, obviously only if it's correctly flashed, trimmed out with proper clearances, and well planned. It seems most cost effective. Keep in mind that cricketing is best done before the roofing, so you may be replacing some roof and will want to make sure your colors match well...but it's only 11 months old so it shouldn't be too hard. Advise your clients not to allow anyone to just plop a crick right on top of the old roof...don't laugh there are plenty of roofers who don't know carpentry and plenty of carpenters who don't know roofing.

One other suggestion, I can't tell what kind of chimney it is. If it's just a gas fireplace vent, it may warrant moving altogether. You'd need to do much more investigating, and if it's a wood-burning stove or something like that it may be too hard to negotiate.

Aaron Miller
03-27-2008, 08:50 AM
Though I understand the need and requirement for crickets or saddles behind certain chimneys I find it interesting that, by adding a cricket, you are also adding two valleys.


Daniel Stone
03-27-2008, 08:58 AM
ok Aaron, picky. Maybe poor choice of exact words. I meant looking down the valley at Michael's framing picture...you've got one going left and one going right around the chimney.
Cut a guy some slack, eh?:p

Aaron Miller
03-27-2008, 09:09 AM
Cut a guy some slack, eh?

OK, but it seems humorous to me that we (A) have a chimney in a valley (which we should not have), and (B) are now adding two more valleys so that we have (C) A chimney in the termunses (termini for you Latin lovers or those short on ink) of three valleys.

I'm waiting on the picture someone sends in of two chimneys is valleys that meet. With the addition then of crickets to those, how many valleys will we have??

:confused: Aaron

Daniel Stone
03-27-2008, 01:15 PM
Tch, Tch, Aaron...if you're going to correct me, please at the very least spell terminuses correctly.

I wouldn't want to have to terminate my tour to this thread because you're determined to tyrrannically truncate our topside tutorial.

brian schmitt
03-27-2008, 01:38 PM
there is nothing in the codes to prohibit this terminus? that i am aware of. the vent manufacture's have gone through all the trouble to make change of direction fittings just so intelligent installers may avoid these pos installations.