Caulking Old Wood Siding

Caulk prevents water from seeping behind vulnerable areas of the outbuilding and developing into rot.

Caulking old wood siding.

Place a full length piece of the damaged siding on the face of the replacement. Even an old outbuilding can benefit from a little caulking. Do ride the smooth edge when caulking a seam between a window and textured siding. Fill any dents and holes with either a wood or epoxy filler.

We used a high quality acrylic caulk on our barn to seal the corner joints seams and trim pieces around doors and windows. Trim boards that sit on top the siding. Caulk by its adhesive nature will try to limit this movement leading to widespread failure and cracking in the caulk over time. Line up the ends and using the old piece as a guide mark the new clapboard with a utility knife.

Most other areas were caulk is necessary should be lightly smoothed with your finger. Caulking on the exterior siding joints at the corner board if done carefully does not need to be smoothed with a finger. Think of a wood home as a living thing. Flashing acts as a waterproofing layer for this type of siding and caulking will prevent the flashing from doing its job.

Siding is often textured and if you slide the tip of the tube along the bumpy texture the bead of caulk will. In the old days the builder would install the trim bring the siding up to it and caulk the corner. Removing all the silicone is difficult to accomplish as there is almost always some residue and when you remove it from wood it inevitably grips onto the wood fibers and pulls them with it resulting in a mutilated work piece that requires lots of repair. Pull out loose nails and renail using stainless steel siding nails.

Be sure to remove any caulk where the siding overlaps as old houses need to breathe. The hole should be about 3 16 of an inch for most caulking joints. The siding expands and contracts with temperature and humidity. When you try to restrict either it is at your peril.

Score the cut line with the utility knife guided by a square. Apply an epoxy consolidant to soft wood and coat the rest with. It needs to move and breathe. Many professionals like those at james hardie also agree that you should not use caulk on fiber cement siding unless there is no metal flashing underneath.

Scoring prevents the wood from chipping when you cut it. When it comes to things like old windows traditional glazing putty is a much better choice.