Stopping/sealing rot on structural beams

[ryanjg117]

(Probably should have posted this in Home Improvement. Mods, please feel free to move.)

We purchased a late 70s tri-level home with structural ceiling beams that run past the roof, showing some definite signs of rot on the top of the beam. As it hasn't rained in about 60 days here in the northwest, I'd like to get this addressed and sealed before the rain comes. What's the best way to address the rot and the best long-term sealant to use?

This house will be painted in the next 12 months, so I'm not terribly concerned with how it looks. But I would like to regain the shape of the beam, with bevel. Wondering if it's best to cut it back an inch or so?

 

[Svar]

I had the same problem. I used marine grade penetrating epoxy from System Three. Wood soaks it in like a sponge. Apply into cracks with a large syringe to stabilize what's left. Then cut the top flat and glue (epoxy) a block of wood to rebuild the original shape.
You could also cut off the end of the beam completely. Not sure what the code says about it. That kind of design with exposed structural beams is just plain stupid.

 

[Pnw painter]

I've used the System Three End Rot system on multiple projects and the products are excellent.

Smiths Penetrating Epoxy is another excellent product and has a longer open time compared to System Three, which can be nice.

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[epicxt]

Ditto what has already been said. I've ran into this a few times here in the PNW and the main thing to keep in mind is you've got to stop moisture and oxygen from penetrating the wood to stop rot. Epoxy products are your friend!

 

[Goz]

I have used Abatron products for similar repairs.  LiquidWood is a penetrating epoxy consolidant. It's used to harden soft or spongy wood. WoodEpox is an epoxy putty. It's used to patch or rebuild missing pieces. WoodEpox is able to be machined with standard woodworking tools after it hardens.

If it were my project, I would remove the worst decay, clean with mildew removing solution, stabilize with LiquidWood, patch/rebuild with WoodEpox, then prime and paint.

Good luck!

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[Svar]

clean with mildew removing solution

Good point! Consider using some fungicide if you suspect rot spreading along the beam.

 

[Klemm]

Another vote for WEST System and their technical support as well as their interesting Newsletter. Nothing wrong with System Three either.

Hans

 

[Peter_C]

I grew up in an Eichler home, for which all seem to have exposed beams. We found the only real solution is to cap the beams with galvanized flashing, or copper would look beautiful. The sun will quickly degrade epoxy.

My parents house required beam replacement due to dry rot, and after seeing the neighbors hired contractor job of sectioning the beams, I decided to build two false walls, cut the roof open, and properly replace the beam. Then giving a section of the old beam for angles to a local metal fabricator, who bent up a nice cover for the replaced beam, and one other beam that did not require replacement. Do it right, do it once and never do it again.

 

[peter halle]

The advice given here regarding epoxies is sound.  Users should consult the manufacturers' literature which will usually prescribe removing the really bad areas.

Festool uses exposed beams in many of their buildings and every time I visit Lebanon I look at the condition of the exposed parallams.  Just habit I guess.

(I went looking for a picture but couldn't readily find one.)

Peter

 

[pixelated]

I live in a log house constructed of milled 6x6's and it's a familiar problem, in fact, I'll be doing one of these repairs in a week or so. As others have suggested, cutting out and replacing the worst of it and then using a penetrating epoxy on the rest has worked well for me. A multi-tool is invaluable for this stuff, you can precisely cut out whatever's not savable with clean edges for fitting a patch. I've been using the Abatron epoxy which works fine but will probably switch over to West System when I run out, just because I have some West system dealers near by.

As mentioned the wood does need to be dry when you use the epoxy, if necessary protect it from rain with plastic or a tarp during the drying. We don't get quite the rain or humidity you get in the Northwet, but if you can protect it from getting rewetted for a week or two, it should dry enough to use the epoxy to consolidate the weakened stuff.

Good luck with it.

 

[ryanjg117]

All done. I went with System 3 rotfix, it wasn't cheap (about $200 in materials, mostly in wood putty) but it sanded and painted really nice. Thanks for all of the advice.

 

[Goz]

Great! Glad it worked out for you!  Any photos of the process or tips on the System 3?

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[ryanjg117]

Great! Glad it worked out for you!  Any photos of the process or tips on the System 3?

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The only issue I had was when combining the wood putty - it's a two part system, combine the white and the brown (1:1 ratio) and work it together until it's completely combined. I *thought* it was fully combined and after applying it and letting it dry, I noticed some spots with isolated swirls of darker brown. This wouldn't dry correctly since it wasn't mixed well enough, but it wasn't obvious to my untrained eye. So, I gouged those spots out and re-applied - this time making sure the putty was mixed, and THEN spending another minute or 2 continuing to mix them in the palm of my hand. Seemed to then cure fine.

It's convenient that you don't need to build the entire putty mass at once. You can let a section dry, re-apply the resin/epoxy to the new hardened puttyy mass, and continue adding layers.

 

[Holmz]

10 mile team borax can be used as a fungicide.