| Outdoor Rot in Homes |
General Protection |
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CPES makes an excellent wood primer for any type of paint. On good wood it spreads a long way, and normal primers can be eliminated, so the expense is not outrageous. There are areas in and around the house that are especially subject to rotting, and these can be treated with CPES, or a combination of CPES and a disodium octaborate tetrahydrate solution application. We recommend that the powder dissolved in water method be used, since it interferes less with CPES penetration than does the disodium in glycol. First, apply the disodium solution, let the wood dry, and then the CPES to seal it in. This combination will give you an almost bulletproof barrier against wood decomposition, especially if particular attention is paid to end-grain sections. Certain areas are obvious: windowsills, wood gutters and surrounding wood, post and column bases, wood framing, and we'll get to some of those in the repair section. There are others that you often don't think about that if saturated with the CPES could save you time and money down the road. Plywood is used frequently in home repairs and additions. Click here to see the results of our testing on plywood panels. |
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DecksWe'll have more to say about decks in the repair section, but if you're building or re-building a deck the application of Clear Penetrating Epoxy Sealer to crucial areas such as plank/joist junctures can save you a lot of work later on. These are the critical areas where nails puncture the wood, gaps exist where water seeps in, the sun warms, and eventually the wood is liable to deteriorate. Most rot starts where water can wick in. CPES applied to these areas in advance can resist problems. |
| Doorway Thresholds Doors and doorway frames can be repaired in a similar manner. Always start at the top so that the CPES™ runs down. Paint/finish must be removed from deteriorated area first so the CPES™ can penetrate. Drill if necessary to get depth. |
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Repair is as follows: First, treat the columns with the CPES™ (Clear Penetrating Epoxy Sealer™), including all the exposed faces, the immediately surrounding wood (after the paint is removed), and the base intersection between column and its support. Next, using a garden sprayer, the insides of the columns should also be treated with the CPES™. Treating the insides of the columns is extremely important, because the wood inside is very vulnerable and CPES™ will significantly reduce the chance of any future wood deterioration. During use the sprayer can be cleaned with lacquer thinner, which will flush the curing epoxy out of the valving. After the CPES™ cures, the hole needs to be filled with Fill-It™ Epoxy Filler. For large open holes, the easiest way to do this is to make a backing surface. There are two ways that this can be done:
The first is to cut a piece of corrugated cardboard 1″ larger than the size of the hole. Bend pieces of wire in half around your finger and push both ends through the cardboard about 11/2″ from the edge of the cardboard in various places. Bend the wire ends outward on the inside. Put Fill-It™ around the interior edge of the hole to secure the cardboard in place. Bend the cardboard so it can be inserted into the hole. Using the wires as handles, pull the cardboard outward. Bend the wire around the outside of the hole to hold the cardboard in place while the interior edge of Fill-It™ cures. After the interior edge of Fill-It™ has cured, cut the wires off flush with the cardboard and use the Fill-It™ to fill in the missing wood. After curing, sand the filler to shape and paint. The second alternative is to fill the inside of the column with enough expandable foam (the canned version sold at home stores will work) to serve as the backing. Excess foam can be carved away after it cures. This method of backing should not be used unless the column is first thoroughly sprayed inside with the CPES™. Foam next to untreated wood traps moisture and promotes wood rot.
To the right is a picture of a less severely damaged column. This would be repaired by removing paint from all affected surfaces, removing any loose wood, saturating the area with CPES™, and then several days (or longer) later coming back and filling all cracks and vacancies with our Fill-It Epoxy Filler. Ideally, the whole base of this column would be treated with the CPES to prevent recurrence of the deterioration elsewhere. Fill-It™ has a compressive strength of approximately 20,000 psi. The compressive strength of the original wood ranges from approximately 4000 to 8000 psi depending on the type of wood. |
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Gutters
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(A) Outside
(B) Deterioration on underside of glu-lam.
(C) Indoors showing glu-lam deterioration.
(D) The beginning of deterioration on the rafter beam. |
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Beam and Joist Rot
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Click on photos to see larger images.
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1) Remove any loose wood and allow the beam to become reasonably dry. 2) Saturate the beam end with our CPES™. Allow the end grain of the wood to absorb all the CPES that it will. CPES will harden any remaining soft wood and significantly reduce the chances of fungi or bacteria returning to infect the wood. 3) Wait for several days (or longer). 4) Fill the vacant area with our Fill-It™ Epoxy Filler, or with new CPES-treated wood bonded in place with the Fill-It Epoxy Filler. The Fill-It will chemically bond with the CPES-treated surface. The beam can be repainted once the Fill-It Epoxy Filler has cured. For those wanting a toned final finish, the Fill-It Epoxy Filler can be colored to about any shade of brown using our Epoxy Coloring Agent. This kind of damage to beam ends can be significantly reduced by pre-treating the ends of the beams with the CPES. Allow the end grain of the beam to absorb all the CPES that it will. |
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Junction points on beams are also prime locations for the development of rot, primarily
because moisture becomes trapped within the joint seams. Picture D is a good example of
what can happen. 1) Drill some small holes to determine the extent of the rot inside the beam, and/or probe with a piece of stiff wire to determine degree of damage. 2) Remove any loose wood. 3) Allow area to become reasonably dry. 4) Squirt, brush, or spray CPES into the area, making sure that all wood has been saturated. 5) Wait for 3-4 days (or longer). 6) Fill with our Fill-It Epoxy Filler. This can be done sequentially, if required; that is, a gross fill which is allowed to cure, and then followed with a finish fill. It will all bond together chemically. Picture E shows exposed interior floor joists, which are deteriorated. Treatment for these requires cleaning the surface of the joists, the removal of soft wood, and then the saturation with the CPES. The CPES will harden any remaining soft wood, and significantly reduce the chances of the rot returning. Again, the Fill-It Epoxy Filler can be used to fill any vacancies. |
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Pictures F, G and H show badly rotted exterior deck beams. The rotten wood has been removed exposing large voids. In this case more than 50% of the wood has been removed and so repair will require bonding in pieces of new wood, or using metal to reinforce the beams. The filling and bonding-in of the reinforcement can be done, after the treatment with the CPES, with a mixture of our Layup & Laminating™ Epoxy Resin and sawdust or wood chips. This mixture can be as thin or as thick as you wish. If the beam extends into the building, the reinforcing material will have to be inserted and epoxy-bonded into the interior beam through augured holes. “Sistering” the beams with new, through-bolted wood is sometimes also a satisfactory solution. Be sure the new wood is CPES-treated for protection against rot, including the drilled bolt holes. If you have questions or concerns about the strength of this type of repair, we strongly urge you to consult with a registered architect or professional engineer. More frequently, the damage to the beam will not be as severe, as in picture I, and the repair procedure should be as outlined above: Saturation with the CPES, followed several days (or longer) later with the Layup & Laminating Resin and sawdust, with our without new wood to help fill. If the deterioration is on the inside of the beam and you wish to preserve the beam face, then the repair procedure is as follows: 1) Remove all loose wood that is accessible. 2) Using a 1/4” drill bit, drill downward-sloping holes into the interior of the badly deteriorated portions. Drill these holes as close to the top as possible. Gravity will pull the product down into the wood. 3) Pump or squirt our CPES (Clear Penetrating Epoxy Sealer) into each bole. Some may quickly leak our of holes or cracks in the sides of the beam. This all happens quickly. Brush-coat any deteriorated exterior portion of the beam with the CPES, allowing the wood to absorb all the CPES it will. The CPES is doing three things: It's inactivating all fungi/bacteria, hardening soft wood, and setting up an epoxy primer base for the subsequent epoxy material. Both the CPES and the resin have a slight amber color, and this will drip down through any exterior cracks or holes. If there are any surfaces underneath that you don't want resin on, cover them with a poly tarp before beginning the process. 4) Wait for about a week (or longer). 5) Using our re-usable caulking tubes, pump pure Layup & Laminating Resin into the holes. Generous amounts of the resin should be pumped in, but not to the point of fill. Holes where the Layup & Laminating Resin might leak out can be closed with 2” clear packing tape, or with cardboard covered with plastic kitchen wrap or waxed paper. 6) Wait for a day (or longer). 7) Repeat the process above, only this time use the Layup &: Laminating Resin mixed with sawdust or wood flour (we sell wood flour if you need it) to make a soft slurry, about the consistency of very heavy syrup, and pump that into the same holes. 8) Wait for a day (or longer). 9) Mix a heavy mixture of the L&L Resin/sawdust, about like heavy peanut butter, load the caulking tube, and pump that into the holes until they are filled. 10) Mix the L&L Resin/sawdust to a thickness that will “hang” and apply that to all vacant areas on the log exteriors. This can be done sequentially; that is, a gross fill followed by a finish fill. This should be as smooth as possible because once cured the mix is almost impossible to sand. Basically, that's it. A strong repair. The color of the L&L Resin/sawdust will be about as shown on this link on our website, along with variations by using our Epoxy Coloring Agent. |
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You can replace or you can repair, if the damage is not too great. If the underside of the deck planks show deterioration up to a third of the plank thickness or less, and the joist the same degree of deterioration, restoration is possible. Sistering new wood next to the damaged joist is advisable. If you have questions or concerns, we strongly urge you to consult with a registered architect or professional engineer, and the repairs done in full conformance with building codes and existing regulations. Restoration begins with the disassembly of the top of the deck. Screws are removed, or if nailed the plank can usually be broken loose from below with a large hammer or maul. Sometimes a few hits from below to loosen and then a sharp strike on top will make the nail stand proud for pulling. Use a pencil to number the planks so that they can be replaced in the same order. Place the planks upside down and using a wire brush lightly scrub the area where plank and joist met to remove any loose, deteriorated wood. Soak the bottom of each plank with Clear Penetrating Epoxy Sealer. If it's important to preserve the weathered appearance of the deck, then turn the plank over within about 1/2 hour and solvent-clean with the Cleanup Solvent to remove any CPES that might have soaked through to the top side. If this isn't done before the epoxy cures, there will be visible patches of epoxy on top. Allow deck planks to dry at least 48 hours with bottom side up. Now repeat this same process with the joists, allowing for extensive and prolonged absorption at bad wood areas. If CPES impregnation is deep, up to 2 weeks may be required for solvent evaporation and epoxy cure. Generally, when the location no longer smells strongly the restoration process can continue. Replace any volumes of missing wood with Fill-It Epoxy Filler. It can be sanded or shaped with normal woodworking tools. When the planks are ready for replacement, put into position and drill pilot holes for nails or screws. This is particularly important if you are going through the Fill-It Epoxy Filler. Sister any joists that require it. We recommend a clear grain fir with few if any knots. Coat the sisters with the CPES, especially the end-grain. Now, at this point we recommend using a 100% polyurethane sealant between the sister and the joist. Our Dymonic® FC would be a good choice. Apply the material to both surfaces, and screw or nail the sister to the joist. When the polyurethane has cured, use a knife to carve away any excess that may have appeared at the top edge of the original joist. Replace the planks in sequence using the same method as above, including drilling the pilot holes. Apply the 2-part polysulfide to the joint and drive the nails or insert screws through the uncured mixture. This is a method used on boats and the life of the repair usually exceeds the life of the deck.
Your deck is repaired. For new construction, we recommend you use the exact same process, and you will have less worry about wood rot or deterioration. Consult with your architect or construction engineer. A couple of hundred dollars in extra materials can save you much more down the road. The exact same procedure can be used with fences. Even the casual application of CPES to end-grains can resist the kind of fence-top deterioration seen in the picture at the right. |
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| UV Light Damage To Wood Click on photos to see a larger view. Wood can be deteriorated by ultraviolet (UV) light. This problem is most common in the southwestern states where wood beams and siding on buildings are exposed to long periods of intense sunlight. Wood deterioration caused by UV light is different in type and appearance from deterioration caused by rot fungi. It is more diffuse and generalized over the wood surface. The softer summer growth is more susceptible to UV damage, leading to greater erosion in these areas of the wood. Beam ends can be particularly vulnerable. The pictures we show here are from a Southern California home. You can see the severe etching of the wood, and the pitted ends. The dark sealer coat is breaking down under the UV light and exposing bare wood. Effective restoration of UV damaged wood requires saturation of the wood surfaces with CPES (Clear Penetrating Epoxy Sealer). The UV damaged wood is much weaker than the undamaged wood, and must be restrengthened if a lasting repair is to be achieved. The wood should be allowed to absorb all the CPES that it will, and this can be a considerable amount on this type of deterioration. The CPES will serve to fill and bond in the tiny spaces that exist between the wood fibers, restoring strength. If protected from additional UV light, the treatment with CPES is permanent. Once in the wood it will not come out. Protection of the CPES treated wood surface requires a coating that is very resistant to UV light. The only clear coatings that can supply this high level of protection are marine-grade varnishes. It's certainly possible to varnish beams and siding, but at least three coatings will be required and it will have to be recoated annually. Not much fun! Opaque coatings, such as paint and polyurethanes, are more practical. Good paint will withstand the UV light for several years, and then have to be repainted. An option to painting is sealing the surface with our UNIFLEX 255 Aliphatic, a very tough polyurethane coating that is totally UV resistant and will last 10-15 years without recoating or losing color. At least two coats are required. You can get additional details on UNIFLEX 255 by clicking here. |
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Termite and Boring Insect DamageWhile termites are the home owner's main concern, there are a variety of insects that can and do penetrate wood. Other insects such as a variety of ants, beetles and bees often simply use the wood for home and breeding space. Their damage is not so extensive, but does provide an access for water to get into the wood. It's not uncommon to see extensive fungal rot in areas where insects have penetrated. Termite and boring insect tunneling is often on main frames or sill timbers, and in due course will cause major structural damage. Most often the damage is in inaccessible areas. Replacing the timber is not always an option, and even if it is, replacement can be expensive. What needs to be done is to restore structural strength to the timber, and to seal the wood so that bacteria and fungi (and insects) won't have access to the interior.
The damaged area must first be treated with a penetrating epoxy (CPES), to harden the wood and encapsulate any bacteria or fungi, and then either a flowable thick epoxy (Layup & Laminating Resin) added to penetrate the insect tunnels or, if access is clear, an epoxy filler (Fill-It Epoxy Filler) applied to build back bulk and bond with the CPES treated wood. The flow-able epoxy must be extremely slow-setting to allow time for it to migrate to all open areas. Our Layup & Laminating Resin is the slowest-setting epoxy we know of. The photos (right) show a badly damaged piece of wood (two pieces, actually, but both from the same timber and both damaged) that were deteriorated by both termites and fungal rot. PHOTO A shows the piece after it has been flooded with CPES and then Layup & Laminating Resin. When the CPES was applied the termites rushed out and were encapsulated. PHOTO B shows a cut section after it had been treated with CPES, but before it was flooded with Layup & Laminating Resin. You can see that the termite tunnels are darkened by the penetrated CPES, but that the good wood remains unaffected. CPES only deeply penetrates deteriorated wood. The dark brown material is rotted wood and termite residue that has been penetrated and turned hard by the CPES. PHOTO C shows a cut section after the termite tunnels were flooded with Layup & Laminating Resin. They are now solid resin, bonded to the CPES, which is in turn bonded to the wood. This wood is strong. You could drive a spike with it. Repairing Insect Damage The repair process is fairly simple: 1) Dry the wood if it is damp. 2) Flood it with CPES, through open tunnels, or through drilled access holes, allowing the wood to absorb as much as it will. If done in an enclosed space, we strongly recommend the use of a cartridge respirator, such as the Moldex unit we sell. Allow the CPES to cure. 3) Wrap any open areas with kitchen wrap (Saran Wrap) to keep the L&L Resin from escaping, and then flood the tunnels with the resin. This may take awhile, because as the resin settles into place you will have to go back and add more. If the voids are large, you can finish the flow with a pourable slurry of L&L Resin and sawdust. Remove the kitchen wrap after 24 hours and you are through. Fill-It Epoxy Filler can be used to enclose large open areas. It will bond strongly with the CPES or Layup & Laminating Resin treated surface. |
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The Rot Doctor, Inc. P.O. Box 30612 • Seattle, WA 98113 Voice: 206.364.2155 • Fax: 206.364.4744 E-mail: drrot@rotdoctor.com |
© 1997-2009 The Rot Doctor, Inc. |
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Our business hours are 6:30 AM to 5:30 PM Pacific Time, Monday-Friday. Tech support is available over weekends. |
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