Guys,
We have approved plans to build a screen porch using 4x4s as roof supports. I’m considering upping the support to 6x6s so I can notch them at the top and bottom and bolt them into the joists (bottom) and header (top double 2x8s). I have to install railings between all of the posts because the porch is 4 feet off the ground. I thought the notched & bolted 6x6s would be more stable than the 4x4s with metal connectors top and bottom. It would also give me more substrate when I wrap the columns with trim.
Any downside to this (besides the expense).
Thanks
FR
Replies
None
I would second "none" but would add that I'd make sure the 6x6's are .40 treated....The heavy ones, dressed on 4 sides
I mention this because I've had some experience with the rougher "treated" landcape timbers where, with ground contact, they were sawdust in about 8 years.
Bing
Think about the visual impact of a trim-wrapped 6x6 before you do that. It might be too big and fat to look decent in your situation. Minimum outside dimensions will be 8½ x 8½ (if you use dressed 6x6s); 9x9 if you use rough-cut ones.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
Thanks guys. The wrapped columns will be about 9x9. The molding profile will match the dining room adjacent to the porch. The design is to have it look more like an outside living room/dining room than a porch. So, the columns will have some "weight" to them, 9 foot ceiling, etc.Thanks again. FR
The other thing is if they're PT and you're notching/mortising, be aware that the penetration of the preservative is often minimal, and you may expose untreated wood. You should probably liberally swab copper green or some such on any cuts.
If its a naturally resistant wood like redwood or cedar, that won't apply.
k
Good point but that is less of a problem if the PT posts are SYP. It accepts the PT chemicals much better than most west coast woods. There is still some untreated wood at the core though.
True about the PT and syp. I'm on the west coast, so it's mostly fir. If you look at a cross section of a cut end, it's like it was lightly painted on the faces.
k
yea... as I understand it, what you all get is worlds different than what is available here. Most of yours is insized(sp?)? I've never seen that here. Here I can get #1 PT boards that are really nice if you don't mind the $$. Plus we can now get this new micronized lumber that is not nearly as corrosive to fasteners and better for painted applications.
Exactly. and even with the incisions, the penetration is like 1/8", unless there's a lot of juvenile wood.
k
Personally, I like using laminated columns for porches. Depending on the look you are after, wrapping isn't necessary, other than just some accent type stuff which can be a cellular PVC type material. Overall you end up with a finished product that will hold up to the weather well.
On the first attached pic I actually wanted to do something more significant with the columns, but the home buyer had fairly simple tastes. These are 8x8 posts which are actually ~7"x7".
On the second attached pic, the corner posts are 6x6 lam posts and the intermediate posts are laminated 4x4s. It was later stained. Maybe a different look than what you are after though.
Laminated columns are somewhat expensive, like maybe $45 - $90, depending on what size you want, but when you figure in the labor and materials for wrapping a regular PT post the laminated might even be a bit cheaper.
Regular PT posts are so unstable that even when wrapped and gapped they can be problematic. A 1" bow is not uncommon, but what sux is when the bow develops after the project is done. We don't know what area you live in though so I don't know what kind of PT you would be working with.
To me, notching the floor joists in (rim board/girder) is a little on the overkill side, but I could maybe see it if the columns were going to act as the floor support posts too. There probably wouldn't be much left of the posts on the corners though so I'm not totally seeing it. It would give a cleaner look than a bunch of brackets though. Lateral stability is always a question with porches, but most are platform framed. It would probably be different if you live in a seismic area.
Matt
The work in 016 is very nice.
Rich
Thanks.
Matt,
Terrific work. I've never worked with laminated columns, but this may be exactly what I'm looking for. I live in the north east. I have to paint the columns to match the trim color on the existing house. I can paint these directly without having to wrap a PT post in azek or windsor one, it will easily be less expensive. Two quick questions, do I need a pole or some support running through the middle of the column or are they structural. And, if I do not need a pole, how do you attach them to the framing (bottom) and header (metal connectors?)
Thanks Matt.
Frank R.
>> do I need a pole or some support running through the middle of the column or are they structural. << They are structural.
>>how do you attach them to the framing (bottom) and header (metal connectors?) << For a wood floor, I'd just toenail 'em with ~3.5" screws at the bottom and use some kind of bracket at the top which will be hidden by the capitol (top trim). You could let the top header into the columns if you wanted to. I don't think it would be necessary unless you were in a high wind area.
Let me say though that I have no idea if they are sold in your area. You need to check at a real lumber store or a lumber speciality store. I've never seen these at home centers.
You mentioned painting. Note that the ones I linked to are "Redried after treatment". Other names for this treatment are KDAT (kiln dried after treatment) or just "Dry". That makes them hold paint much better than regular PT with much less movement and very minimal checking.
Beautiful work on the City House.
Matt raises a good question. I would like to use lam columns atop cement block & stone veneer piers with a flat capstone.
SteveVA
Edited 2/20/2009 9:33 am ET by SteveVA
Treated posts have a well known tendency to twist as they dry down.
That may not matter in a pole barn, but for the wrapped column and railings you have described it will be a mess.
As suggested...at least laminate 2x6's.
Use at a minimum hot dipped fasteners...better yet SS. The same goes for the nails/fasteners that you use for the wrap and rails where the fasteners penetrate the ACQ.
.........Iron Helix
One thing I'm thinking here, and it may get some grunts but f it they are really heavy. If I can do it with a 4x4 I will. I've often wondered if it would be effective to wrap a doubled up 2x4 post with ice and water. Then Dress the post with clear pine or azeck.