I need some advice on a project I am planning. I built a deck on my house a few years ago with the plan to cover it and screen it later on. Well, later on is here and now I am considering my options for framing materials. The deck has PT framing and cedar decking, and has been built with support for the roof in mind.
With regards to framing, my question concerns wood species. I was planning on using PT posts to support the roof system, 6X6 to match the existing railing. Plus, I like the beefier look of the 6X6. As for the rafters and carry beams, do you think I need PT there too? My alternative option would be white pine, which is available from local sawmills pretty cheap. I don’t plan on windows or turning it into a 3 season room, so exposure is my consideration. I love the look of fir, but it can get pricey in a hurry. I am open to suggestions, so fire away.
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I usually think that the beam work should match whatever you choose for posts. But I really don't like seeing long PT posts in exposed situation as they tend to twist or bow when they dry out. If the screen work is attached to them this could really create a headache. But at least you're planning on 6x rather than 4x. Rafters and CJ's shouldn't be a problem using KD lumber. Even better if you're going to have some sort of finished ceiling like vinyl or beadboard or something. Are the rafter tails exposed or is it a boxed in fascia/soffit?
Edited 4/13/2007 10:55 pm ET by dieselpig
I am worried about the twisting and bowing of the PT posts as well, but I don't know of any other option. The screening will be two pieces for each section, a lower behind a railing and an upper above, both semi-removable. This may make it less of a headache, or it may make no difference at all. If I used PT rafters I might leave the rafter tails exposed, but most likely I would at least cover them with fascia and drip edge. In that case, the rafters wouldn't have any direct exposure to rainwater. The framing would be exposed underneath, with 1x6 t&g over the rafters and under the roofing. I really wish there was a way to get affordable 6x6's and 4x6's that wouldn't twist up so much. The house is a fairly rustic timberframe, so the porch framing doesn't have to be too refined. On the other hand, if I have to rebuild all my screen frames next year, that would not be good.
Just an update on my research so far. I spoke with several professional timber framers and they indicated that while they offer clients the option of selecting cedar or KD fir for outdoor posts on porches and covered entryways- at 3-5x cost- they very often use green hemlock or white pine. They say the fact that it is a vertical post at least partially covered by a roof seems to give pretty good lifespan to the wood. The white pine is more stable (twist/warp resistant) than the hemlock, while the hemlock is more rot resistant than the white pine. These guys are pros, so I don't really have any reason to doubt them. Still, I am surprised.
What do you think?
If you elect to use w.p., detail the bottoms of the posts so the constant wet/dry won't cause premature failure. That will be the key point of concern. In addition, any other joint that will be exposed to weather-your rail connection for instance.A great place for Information, Comraderie, and a sucker punch.
Remodeling Contractor just outside the Glass City.
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I could use post standoff bases (the hidden type) to keep the post off the framing slightly and maybe seal the end grain with something like West Systems epoxy or polyurethane glue. Maybe even coat the area where the railing will attach to the post with the epoxy as well. That should buy me a few more years, I should think.