In Search Of Rot
Before you do anything, determine whether the damage was caused by accidents and normal wear and tear, or rot. Rot can be distinguished from other kinds of damage by its dark, charred appearance and its soft, spongy feel, but it’s tricky stuff. Rot may be eating away at wood under a camouflage of peeling or rippling paint. Or it may masquerade as a small, harmless depression in the wood while it destroys the entire piece from the inside out If you find a little rot, probe the area with a narrow screwdriver or chisel. Chances are you’ll find more.
Filling rotted wood presents some special problems. The wood rotted in the first place because it was repeatedly exposed to water. ff you can keep water away from the wood by caulking a leaky gutter or redirecting a down spout, do that first.
In all cases, damaged wood must be thoroughly dry before you can make any repairs. Patching wet wood is like locking the fox in the hen house. It will trap moisture precisely where you don’t need it, creating a perfect environment for further rot.
Tools of The Trade
Here’s what you’ll need for your wood repair project: a chisel or screwdriver to dig out loose or rotten wood, a drill and 3/16-in. bit, a Phillips screwdriver for drywall screws, rubber gloves and a paint brush or squeeze bottle to apply the consolidant (a hair dye applicator from a beauty supply or drugstore works well; about $1.50 each). Use plastic disposable putty knives and mixing containers. You’ll need medium-grit sandpaper, and depending on the shape you want to make, a utility knife, a rasp, a plane or files.
Tricks of The Trade
Using these fillers and consolidants is like eating hard-shell tacos in rush-hour traffic. Making a mess is inevitable. So keep plenty of rags handy. Clean tools and wipe up spills right away. Once this stuff hardens, your only method of cleanup is chipping and sanding.
All of these products stick to wood like gum sticks to your shoe. But if you’re filling a deep hole (1/2 in. or more) drive a few drywall screws into the repair area, leaving the heads sticking out. Use screws that are long enough to go an inch or so into the wood and still be about 1/4 in. below the surface of the finished patch. This will give the repair an even better hold on the surrounding wood.
These fillers tend to droop when applied to vertical surfaces. So if you’re making a flat or square repair on an upright piece of wood, you may want to make a simple wooden form to hold the filler in place. To prevent the form from sticking to the patch, line it with a heavy plastic such as 4-mil polyethylene (available at home centers for about $4 a roll) or freezer bags.
Because these products harden so quickly, applying them is a bit like emergency surgery. Once the filler is mixed there’s no time to search for an extra putty knife or settle a dispute between your kids. So make sure your tools, rags and repair surfaces are ready to go before you start mixing.
Don’t mix more than a handful of filler at once. Several small batches will give you more time to work than if you mix one big batch. Clean or dispose of mixing containers between batches. Chunks of dried filler from the previous batch will mar the surface of the repair when you try to smooth it.
Don’t expect to get a perfect repair after one application of filler. Even if you’re making a simple, flat repair, you’ll probably have to sand the patch and apply more filler, perhaps two or three times.
The Pros And Cons of Wood Fillers
- Often cheaper and simpler than replacing wood.
- Easy to use. Mistakes are, for the most part, reversible.
- Can be planed, sanded, carved and painted to perfectly match any existing wood pattern.
- Designed to withstand outdoor conditions, but excellent for interior repairs too.
- These products will take stain, but not at the same rate as the surrounding wood. So expect color differences.
- When applied to wet or damp wood, these fillers will promote rot.
- These are toxic chemicals, so they present some dangers if not handled properly.