Replacing porch boards

[aislinn]

We have three porch boards that are getting bendy and we’ll need to replace soon. The wood is not standard width and I’m just wondering what my options are for finding replacements? They’re about 5 11/16 inches. The previous owners did a horrible job patching a small section so we’ll probably fix that at the same time.

[Gothichome]

Aislinn, a picture would be nice. Timber for our old homes are usually full dimension, judging from the width you posted I would suspect the board is a 1x6 tongue and groove board. As to replacements, check out your local salvage yard. If that is not the answer I think, (if you have the means) you can make new from full dimension boards.
If I need small amount of full dimension lumber, I usually buy barn boards, use my belt sander to smooth the exposed side. An ordinary table saw can cut both the tongue and the grove, a router can also be used.
The big issue though with barn boards, they for the most part are not kiln dried to the same level as modern boards, so they tend to warp if not nailed down in short order. Also, if left out in the sun they will warp in really fast. When I buy my boards I look for boards with very few or no knots. You may need to sort through a dozen boards or so, at least that’s been my experience.

[phil]

if it's a small amount you can trim down from a 2x8. you didn't say what the thickness is?
I think you can get pressure treated with rounded corners if you want gaps. If it's T and G then you need that. and if it's a whole deck I'd consider fir, cedar, IPE, pressure treated and maybe some of the new composite materials if it is exposed. maybe you can buy ship lap an cut that to fit. the length is another thing to consider since you may not want joints.

my front and back porch had plywood and I put new 3/4" plywood and fiberglassed it. not original but I like it here because we get so much rain and it lasts pretty much forever, like an upside down boat. that also made mine dry underneath. If your porch is covered then you probably dont need the most expensive thing going. If you need 5/4' ( 1 1/4" ) you might check a hardwood supplier. If you want fir maybe talk to a small mill if any exist near you. people with little bandsaw mills can saw to those odd dimensions, but hardly worth bothering them if it's only 3 planks you need. If you redo the whole deck then you can change the plank width , if it's a patch you wont want it to show. If its temporary you might consider just filling the dangerous area with 3/4" marine grade plywood or even laying a sheet of plywood down just so no one can fall through.

the thing with decks is sometimes they aren't sloped right or sometimes the design allows to retain trapped water. If you can keep the ends of the planks dry it helps them not suck water in and swell up. If you lay it too tight that can reduce it's lifespan. you want enough gap so it does drip if it is meant to dry out that way, or to allow for wood expansion and contraction if it is laid "tight"

if you plan to tear off the decking then check the framing too because sometimes one leads to another. cedar has good rot resistance but it isn't too hard so it dents. fir is a happy medium with fairly good rot resistance. Pressure treated lower grade lumber might be cheaper. If you want vertical grain lumber that's more expensive than flat sawn. What is yours now?

[aislinn]

Sorry here are some photos! It is a roofed wrap around deck and rather large, and the rest of the wood seems to be fine. It's just the part where the stairs are and its more exposed, which makes sense.

[phil]

Thanks for the photo it helps.
What happened here is that the 6 inch T and G probably wasn't that available so rather than cut new stuff to match from 2x8 they used 2x6 which is narrower. the gaps are ok they will help it drain there.

the top of the steps is exposed to the rain and those planks had their end grain to the weather so the planks didn't last.

It's normal for a board near the edge to skirt the job in order to prevent the endgrain from being exposed like that.

Id cut them all the same length and just run those few planks parallel to your steps, that way gap and width is not an issue. Just try to get the same thickness even if that means adding shims or something to bring the height to the same.

I'd look for T and G fir if you can, but obtain the lumber first, then you can cut it to suit so the width can be divided by the number of planks you are adding. You might need to double up on some underneath structure so you have something to nail into but try not to double up lumber too much as this can cause a place for water to stay trapped and not dry by the air and cause rot. any time you have planks "sistered" capillary action will pull water into the gap.

Id leave the two planks that are captive under the railings alone and the spacing is equal there so if you run the others parallel to the steps it wont look funny. I'd use a router to run a roundover on the plank at the top of the steps just so it looks a bit more finished, and do the same to the steps if you change them, but that's optional.

if you like you could keep the repair to the size already laid out in the previous repair , just make the new patch a bit wider to divide it evenly. there is probably something to nail to at the meeting point, when you remove some you can check the structure and see how things are supported, You might end up adding some pressure treated lumber underneath if needed. Try not to open a can of worms, if it feels solid enough , leave it alone.

[aislinn]

Thanks so much this is helpful! I need to go find some photos-it will help me visualize it!

[Gothichome]

Aislinn, Phill’s got you going in right direction. Bullnose the top step between the posts, and replace those boards. I would replace the whole board though, it would blend in better with the rest of the porch and won’t look like a patch.

[aislinn]

Thank you so much Gothic and Phil! I will post a picture when its actually done!

[phil]

Thank you so much Gothic and Phil! I will post a picture when its actually done!

good to get that promise in writing

if you want boards the same width you could cut 2x8 into T and G and use the dimensions you have. I would not use the sort of lumber you find at HD, but instead look for fir if you can or another wood with better rot resistance. If you use pressure treated you can check what fasteners are compatible some screws have a coating for that purpose. If you cut into the P/T lumber you'd want to use a paint on product to slow the rot. I'd just use fir but its not the absolute best for rot, but it will fare a lot better than spruce, pine etc.

My neighbor used IPE for his whole deck. Its super hard so you have to drill holes etc but lasts a long time in full rain.

the stringers on the front of my house lasted 90 years in full rain sitting on concrete with full contact, but that was good old growth fir. I could tell they were original by the imprint they left in the wet cement during construction. The newer composite decking materials probably last forever but might look a bit less "historic" and may not come in that thickness.

[aislinn]

Finally got the project done! We ended up using boards from our back porch that were half rotting and needed to be replaced (we have plans to enclose that porch in the next few years and make it a mudroom). Not perfect, but I'm happy with it! Now just need to scrape the porch and paint...