*
Basic framing question:
I am building a 12′ x 16′ screened porch, one 16′ side being parallel with and bolted to the house floor system. All framing is standard platform framing with a gable roof. The gable end wall is the 16′ dimension. The porch floor system is supported by 5 6×6 posts, 5 footings, and the house. My question is, does the 4×4 wall posts for the screened walls need to be placed above the foundation posts, or can I put them where I like?
I would like to break the 16′ wall into 4 screen panels in which case 3 of the wall posts would be stacked on top of the foundation posts/footings – no issue here. However, on the two 12′ walls I would like to place a ~2-8 screened door in the middle of each wall – directly over the mid wall posts, and flank the door with 4×4 wall posts. For bullet proof construction, the support should be carried all the way from the footers to the roof – in a plumb line, but I’m not sure that this is necessary?? What do you think?
Please see attached drawing of porch footers and floor system.
TIA
Replies
*
The 4 x 4 post locations will be fine, as far as the box beams and your 6 x 6 posts are concerned.
You will have to use some sort of header at the top of the 4 x 4 posts to spread the roof load, however.
*MattOur building code in Ontario allows for a maximum 2' offset in the vertical line of loadbearing. Your box beam construction should be easily sufficient to absorb any load transfer, or, if you have the option, why not plan the placement of the footings and posts in the two 12' walls to coincide with the upper post placement.You're drawing shows your floor joists running from right to left, I assume an error here, and they are meant to run front to back with a 12' span!!! Even though that puts the joists at right angles to the rafters, in a porch with one side attached to the house this isn't at all critical!!-pm
*Hi Matt, As I see it you should do a couple of things. First of all you need to change the direction of the floor joist' so that they run the 12' dirction. 16' is a very long run for 2X8 framing in a deck. Second, in my area (Massachusetts) the framing for a deck is subject to greater load requirements then the framing for any interior floor. So, I would suggest that you venture down to your local building inspector to find out if you have to meet the same tough guidelines. If I got out my code book I would bet that It required a minimum of a 2X10 or posibly a 2X12 frame with a 12' span.Sorry, its 3 floors down and thats just too far to walk tonight! Perhaps some else would know? As far as the doors and posts are concerned, don't sweat it, you can easly ofset the 4X4's by the 16 or so inches that you need on either side of the doors. There is only a roof load above and you seem to have plenty of support under the 2X10 doubles.
*Jay:Thanks for the reply. I neglected to say that the roof has already been framed and is currently being held up by temporaries. This may seem a bit odd, except that the framers who built the house did not do the porch - just the roof structure. Seemed a bit weird to me too, but he had a pretty good idea of the way he wanted to do things - but I won't go there here!Anyway, the porch ceiling is 2x6 joists with a double 2x10 flush beam around the perimeter.
*MattMissed the cutoff to edit my message. . . in Ontario 2x8 #1 Spruce @16"oc can span 12'-1" at 40psf live load and 13'-4" for 30 psf live load. Check your local code re design loads for porch decks.-pm
*Patrick:Yes, the direction in which I showed the porch floor joists running was a drawing error.The entire structure, with the exception of the screen walls is all complete. Some more advanced planning on the footer locations may have been better, but I think the engineer just placed the footers based on the minimum that was required to support the load - not taking into account door locations and screen panel sizes - which is really the root of the issue - I don't want any more wall posts than are necessary as the screen panels will be all chopped up in small pieces - say, 3' wide.I am pretty sure our building code (CABO) gives no specific guidelines for this instance.