I've been putting off replacing the floor boards on my front and back porches for years, but since I'm getting a home equity loan to replace the furnace and windows maybe I'll work on the porches too.

The boards now are tongue and groove - I've been to a couple big box stores and didn't see any - are these available or do I have to mill my own? My rear porch is over the basement so I can't just use deck boards. I need the weatherproof seal.

Also, the boards have some decay which allowed the roof support post to fall below the floor level. What is the easiest and safest way to raise the porch roof an inch or two until the floor boards are replaced?

Thanks for your help,
Tom.

BTDT
Bracing the roof where the roof load is held, i.e. whatever supporting beam is there, and jacking it up, slowly, with screw jacks or the like. I say slowly because if you try to move a sagged roof 2" in ten minutes you're going to break things. You live there, you have time, start with good tension on it and do a turn a day until its level.
You can get T&G flooring products but are they suitable for exterior use? Thats one question. And what kind of elements will they contend with, that's another. If your house has any curve features, then you're milling your own, on site, as you go, to get the tapers all correct and pointing like they should towards the center of the magical pivot point.
I'd look for tight grained SYP or VGDF, I'd seal it all around as I installed, and topcoat the whole thing. Whether thats an exterior clear coat or paint, that's up to you, but I would not leave any exposed wood at all, no tongues, cuts, anything.
A nod to Penofin, my fav thus far in exterior wood treatment. Its a good product, its simple, effective, repeatable, looks good, easy . . . what more could a guy want?

Well, Tom, I deal with this issue several times a year. More often then not the job turns into a much bigger job than the client expected. By the time the floor has rotted away so much the porch post is sitting on the framing there's usually so damage to the framing also. Another possible problem when the porch post falls through the rotten flooring (and sometimes the framing too), the gutter may not have any flow. Water can collect, if you have a box gutter this can rust away the tin, this rots the soffit. Or the water can over flow and run down the fascia, rotting it and the flooring when it makes it way there. Like I said, these things aren't always as simple as you may thing at first glance. I'll offer a bit more advice if like in the morning. Give us a little more info on the type of house you have, that will help to give you more specific answers.

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BurrellCustomCarpentry.com

Is it ok to use treated lumber for the floor boards? How long is the usual wait before these boards can be painted? Or is it better to use clear wood and seal it?

RWeber, I hate to admit this, but I'm not real sure what a screw jack is. Are you talking about the automotive kind or the type they sell to use in basements (support posts)? I only need to raise the roof about an inch in order to replace the flooring.

Brice, I don't know what you need me to tell you about my house. It is a two story, the back porch is about 5' x 8' and has one support post (the porch roof attaches to the house along the back and one side), the front porch is the width of the house, has 4 support posts and the roof just attaches along the back. I know on the back porch I need to replace the boards that support the flooring also.

Thanks for the help and let me know if you need more info,
Tom.

Yes thats the kind I'm talking about. One inch, in the grand scheme of things, isnt too bad. I usually put a pad under them on the ground if I can't get to rock or solid framing (which usually, if you put it there, its in you way later) and just use 2x12's to spread the load out.
You can use PT. Its low on aesthetic but that one is really up to you. It is not an ideal paint surface and will likely take months to dry. Around here with our seasons, if you laid it this summer, you can paint it next. But don't get high aspirations. You'll need to sand it smooth (and not breathe in the dust) and prime it good.
I guess I say that because while I've seen painted PT before, I have yet to see any that really looked very good.

I rebuilt my front porch a long time ago and learned a lot. I also have a friend who was involved in the restoration and maintenance of a collection of Colonial era houses. A lot of what my friend told me about what happens to wood when exposed to the elements (painted or not) could be seen in my 100 year old porch.

The first lesson was that what ought to be done often isn't. For example, tongue and groove flooring shouldn't be used outdoors unless the wood is something like Ipe. There is no finish that can protect it over the long term and the T&G is is moisture trap.

If a wood flooring is used that needs to be protected by paint you need to provide a way for the rain to drain off the surface quickly and not get hung up between the boards. So, the boards need to have smooth sides and be spaced about an 1/8" apart for the water to drain. All the edges need to be rounded so the paint can shrink around the corner without cracking on a sharp edge. All six sides of each board needs to be primed and ideally top coated before installation, with a final finish coat after nail holes are filled with an oil based filler.

Another lesson is that joints are very slow hinges. My old porch (kind of low end Victorian style) had L shaped pedestals on each corner and three short columns sat on each pedestal. As originally built the pedestal sat on the T&G floor boards which slowly sagged as decay set in causing the pedestals to go one way which allowed the columns to go another way so the structural support for the porch roof eventually began to resemble a very slowly collapsing chain.

There should only be two joints in a structural support such as the post holding up a porch roof. The one at the bottom where the post sits on the foundation and the one at the top where the roof joists sit on the post. The floor boards should be cut to fit around the post which passes through them. In my case I had to split two of the new columns to fit around the two structural posts.

In the case of my porch floor I learned about the separated and separately finished floor boards too late. I had already installed T&G Doug fir and had to scrape and paint a few times because of the paint cracking on the edges of the milled sides before figuring out a solution, unfortunately before Festool arrived. I milled off those square edges by running a router with a V bit down the joint between each board making a 1/4" wide ditch. I softened the edges a little with sandpaper then primed, caulked, and repainted the whole thing and now I only have to deal with scratches and general wear.

Tom,

There's lot's of good advice here, so I won't add much. One thing... Posting pics will help. It's difficult for us to understand the details without them.

Remodel projects can be tough (DAMHIKT ). A key problem is that you'll probably find unexpected surprises when you start tearing things apart. For example, you indicated that the floorboards had some decay and the floor was sagging in one spot. The first order of business is to find out WHY this is occurring. I.e, pull up some boards to check out the structure. Scope out the details before starting.

Regarding raising the porch... Take it VERY slowly. When I jacked the joists in my garage, I hired an engineer to give me some advice. He recommended raising it no more than 1/8" per day.

Below is a pic of my garage while jacking the joists. I used adjustable screw columns (Adjustable Steel Columns) against a 4X6 beam to raise the joists before sistering them. Toward the end, I had to use a hydralic jack under a temporary column to relieve some pressure to get the screw to move.

If this is a solution that you need, make sure you check the rated load before purchasing the screw columns. I bought the cheaper ones and had one bend. I had to go back and get the heavier ones.

Regards,

Dan

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Wow Dan, there sure is a lot of metal in this shot!

What!?! You thought I was a woodworker?!?

Regards,

Dan.

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And I only see two systainers...and a Bosch SCMS!

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