How To Repair Notched Floor Joist

A Question from a Reader – Those Plumbers!

Q: I recently had a contractor provide an approximate for putting downwardly a vapor barrier in my crawlspace. While he was down there, he constitute several places where plumbers had badly damaged the flooring framing. Should I believe him? –Ashlynn One thousand., Clayton, NC

A:Hi Ashlynn, Ask the contractor if he could provide pictures of the damage, preferably with adequate lighting. It's entirely possible he'south being sincere; I accept seen this happen in numerous instances over the years.

New Homes vs Old Homes

Plumbers installing supply and drain lines in new houses rarely practice annihilation to compromise firm framing. If they exercise, an inspector will pick it up before the house is put on the market.

Still, in older houses, remodels and repairs occur adequately ofttimes. Unfortunately, plumbers or HVAC installers sometimes harm your framing.

Good Plumbers vs Bad Plumbers

Plumbers need to situate pipes and supply lines at very precise angles, and in very particular places. GOOD PLUMBERS always make sure that their lines penetrate the floor in areas costless of framing. If necessary, they even insist that framing changes exist made to allow for clearance.

However, BAD PLUMBERS sometimes install pipes wherever information technology is easiest or nearly convenient. (Like in the top picture). When that happens, they remove nearly all of the joist'due south strength. And, this creates a condensation-rot situation!

Bad Plumbers Do This, Too!

An even more frequent problem is "notching". To traverse the crawl infinite at a certain top, they sometimes notch the bottom of a joist. (Pardon the quality of the pic below. It was taken from the prone position in a nightmarishly pocket-sized infinite.)

Information technology's hard to come across, but the plumber has cutting a notch in the bottom of the joist!

This is almost as bad equally the vertical bore. Cutting through the underside of a joist drastically reduces its "span" strength. That's the corporeality of load information technology tin conduct over a specific altitude. (Here's a really comprehensive link for the informational span tables of southern pine.)

The proper way to handle this state of affairs is to pass the pipe through a hole in the middle of the joist. That manner, material around information technology on all sides tin easily compensate for the pigsty.

However, feeding piping through a series of these holes in a tight space is often logistically impossible. Rather than finding a better way, bad plumbers have the like shooting fish in a barrel way out. They notch the joists instead.

Pro Tip

If you have notched joists in your crawlspace, the problem can exist mitigated by "sistering". That means attaching a companion piece above the notch to assistance behave load.

I "sistered" this joist to recoup for the notch.

The procedure really isn't that complicated most of the time. Simply, it volition profoundly increase the force of your floor system. Shoot a lot of fasteners in a continuous "W" pattern. That fashion, you necktie the new member to the old one.

A More Complicated Set

Carpenters occasionally shorten and span framing members to permit for drain line penetrations. Here'due south a adept blithe video tutorial on how that is washed.