The Rot Doctor


Subject: Rot problem in glu-lam beam
Date: Wed, 18 Aug 1999


We have a glu-lam (doug fir) which has rot on the end where it sits in the saddle bracket on top of the post which holds up the nook. The adjoining beam was so badly rotted we need to replace it. The end of the beam with the rot appears to have three or four really bad spots into which I can stick a screwdriver, from the end, about 5". The problem was caused by no sealer or paint on the end of the beam and no caulking.

I'm drying it out with a heat lamp pointed at the end.

Can your products be used to stop further rot and possibly toughen it up enough so it won't fail with the weight that's on it (currently it is holding it up without any sags etc.)?

What process would we use, what products, to accomplish this repair?

The adjoining replacement beam is pressure treated with about 2" penetration of copper something-or-other, which is what was instructed be done for exterior use.

When completed, the installation and existing (rotted end) beam will be covered with galvanized flashing, and all joints and openings sealed with caulking.

Could you suggest a "program" to repair this damage, hopefully make it strong enough so it won't collapse in the future, and advise if the other things we're planning to do are correct?

I guess the big thing is kill the rot spores, seal the mess, and keep it dry?

Thank you!

For your particular situation I would recommend the following:

Assuming that the deteriorated wood is dry, I would drill a few access holes from the top (best) or the sides (next best, downward sloping) and infuse as much CPES (Clear Penetrating Epoxy Sealer) as the wood will absorb. Also apply CPES by brush to the end-grain on the glu-lam, again allowing it to absorb all it will. It will penetrate deeply by this method alone. Give this a few days to cure and for the carrier solvents to evaporate away. Then go back and using a kitchen baster apply into the access holes as much of our Layup & Laminating Resin as the wood will absorb. This is a slow-setting resin that will also leach throughout the deteriorated area. This is a slower process; patience is required. Cure time for the L&L Resin is 24 hours to hard, 48 hours to full.

You have now killed all rot fungi and established strength to the deteriorated portion of the glue lam that will at least equal (and probably exceed) its original strength. It should not rot again.

For the new beam I would apply CPES generously to the end, if it is accessible. Some should be absorbed, and it will protect. Pressure treated wood is fine, but varies widely in quality of treatment. The CPES will be more of a guarantee. CPES should also be brushed over all available exterior wood in the general area.

The caulk seems good but is not always, because it has a tendency to trap moisture, which allows it into the wood, which gives the rot fungi what they need to grow. In view of the CPES/L&L Resin reconstruction, and of the pressure treated/CPES treated new beam, I would give it a galvanized cap for water drip protection buy forgo the caulking. That way moisture has a way of evaporating out.

This program should take care of your problems. We suggest that all new wood going in be treated with CPES, especially the ends, which is where the rot usually starts. It doesn't take much CPES and it can help prevent a lot of problems in the future.

Come back if you have additional questions. You can order product directly from us using on-line order form, phone, or fax.