I have a single story home in California, with a concrete slab foundation and a laundry room located in the hallway. The dryer vent connection is just a PVC pipe running down into the slab, and then in the front of our home, there is a 90 degree PVC bend that spits out the exhaust (and sometimes some lint):

Weird exhaust

Now, I'm not an expert, but I'm pretty sure that's not how dryer vents should work. Seeing as I can't really dig up the slab or anything crazy, should I:

a) Continue using this vent, if it's safe to do so? If so, should I put a screen or something to keep critters/bugs out? b) Hire a contractor/handyman and run a new vent through the wall/attic, and out to the side of the house somewhere?

  • 1
    The code citation below makes sense in an ideal world. If you're concerned that your dryer could generate enough heat to melt/ignite the existing pipe, then by all means change it. (Going out the roof or the end of the house is probably not too hard.) I'd be concerned about lint buildup in the elbows and I'd certainly put a bug screen on the exterior. Jul 17, 2015 at 13:43
  • 1
    Once it's in the slab, the fire concern (which is why it's supposed to be metal) is pretty minimal - the pipe & lint could burn, but the concrete won't. If you can get a cleaning snake/brush through it for the lint, and change the part above the slab on the inside to metal, I'd have little concern about using it. I would use a normal dryer vent termination with "flappers" - in my experience even a coarse screen that will stop no bugs becomes blocked with lint (this despite the fine-mesh lint trap at the dryer.)
    – Ecnerwal
    Jul 28, 2015 at 3:08

1 Answer 1


The duct is supposed to be smooth walled metal 4" in diameter, unless otherwise specified by the manufacturer. So, you should probably not be using PVC.

International Residential Code 2012

Chapter 15 Exhaust Systems

Section M1502 Clothes Dryer Exhaust

M1502.1 General. Clothes dryers shall be exhausted in accordance with the manufacturer’s instructions.

M1502.4 Dryer exhaust ducts. Dryer exhaust ducts shall conform to the requirements of Sections M1502.4.1 through M1502.4.6.

M1502.4.1 Material and size. Exhaust ducts shall have a smooth interior finish and be constructed of metal having a minimum thickness of 0.0157 inches (0.3950 mm) (No. 28 gage). The duct shall be 4 inches (102 mm) nominal in diameter.

NOTE: I'm not familiar with California building code, or local amendments that may exist. IRC is a common building code, and lots of other building codes use similar standards.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.