Porch flooring -to space or not to space
I am getting ready to renovate a coverd porch on a 100+ year old house. I have to replace the flooring on this porch (approx 10′ x 14′). It has been patched many times over the years and has buckled in many spots (all of the problems are at the end grain on the southern exposure). There were many problems in the past which have been or will be corrected first (leaking gutters/roof, little to no floor slope, poor air circulation below, etc.). I plan on using 5/4″ x 4″ T&G vertical grain Doug fir. I plan to pre-prime all but the wearing surface of the boards prior to installation with a quality oil base primer. After installation I will sand the wearing surface, prime and apply two finish coats.
My first question is whether to leave a gap between every third board (to be filled with butyl rubber or polyurethane caulking) as a means for the floor to expand and contract to help prevent any future problems (here in Western NY, winters are frigid and summers humid). I don’t typically see this done but I do see a lot of porches with the same problems (buckling, etc.). Am I over-analyzing/over-killing a simple job or is this reasonable. I also don’t want to create a different problem by placing the caulked joints on a wearing surface, and having the joints fail from foot traffic (typically I despise the use of caulk, and use it only were absolutely necessary).
My second question is should I place a border around the outer perimeter of the porch (creating a bullnose edge on a piece of stock). Along the long edge (14′) of the porch, all the end grain is exposed to the elements (a southern exposure). Placing a border may help protect the end grain from sun, rain, and snow; but I am afraid it may become a water trap (the slope of the porch will be parrallel to the direction of the decking, the border would place a joint that crosses the slope). Another problem if I don’t leave gaps in the deck boards as discussed above is that the expansion and contraction of the deck boards will blow out the miters at the border corners. Even if I spline and glue the border on, I fear mother nature will win and open up the miter joints.
Any suggestions or techniques would be appreciated!
Replies
The border sounds like a good idea. In furniture making this might be called a breadboard end. Put a tongue on the end grain of the decking and a groove along the edge of the border. On table tops this is fastened using a slip dowel joint. Basically a dowel fits tightly through holes in the end(cap) board and through an elongated slot in the tongue. This allows latteral movement of the deck boards. Maybe you could just pin it in a couple of spots. Watever you do, don't glue this board along its length, it will never hold.
You shouldn't need to miter the ends. You will have just a small area of endgrain showing. Sand this endgrain smooth and prime and paint as normal.
Hope this helps.
Mike
Back in 1990, the father in law needed 2nd floor porch floor rebuilt on 1840's home eastern PA. Exact same problems at outside edges of old boards. We used PT framing with VG D Fir 3/4" x 3". Primed all 4 sides with alkyd base and then caulked every joint with polyurethane caulk during install. Slammed every board as tight as possible. They are only going to shrink after install, trust me. We fixed the roof and the gutters. 13 years later, we have maintained with paint and it looks great. Including the 30 lineal feet of exposed ends which have plenty of paint on them.
If I were you, I would skip the bread board end, you are right, the joint will crack after 1 year and collect water. Besides, if someone steps on it, it will break off. You are going to sand the whole floor ? Wow. I don't know too many people who would pay for that around here. I'm sure it will look great.
carpenter in transition