Wood – Level of repair for rotting outdoor stairs

repairstairswood

I've got wooden stairs leading up to a porch that need repairs. The more I look into it, the more that I see needs to be done, so I'd like advice as to what I should do short term and what I can put off.

Here is a summary:

  • About 10% of the tread boards are clearly in need of replacement. For one, my foot went through it.
  • The stringers have rot where the nails from the rotten tread boards were. The rotten wood goes 1" deep.
  • Other rotting near the bottom of posts that is cosmetic rather than structural.

I have pictures below to illustrate.

These are the three levels of repair I am considering:

  1. At a minimum, I need to replace the 10% of the rotten tread boards and use putty on the stringers.
  2. Replace all of the tread boards and patch stringers where needed.
  3. Rip everything out and rebuild. I'd like to put this off for a few years because the rest of the porch needs work as well.

The criteria is that I'd like the stairs to last another 5 years or so until I do larger renovations on the porch, and to minimize the amount of needed work until then.

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Best Answer

Obviously you have to replace the bad treads. The bigger issue is the stringers. Unless you remove all the treads and trace one it'll be difficult to accurately match the current shape. For that reason, and assuming that the rot doesn't substantially weaken them, your best bet is patch blocks.

I'd cut lengths of 2x6 to about 16" and screw them to the stringers, level with each tread cut and flush with the riser cut. They can extend out the rear somewhat, saving fitment effort. Use four to six 3" corrosion-resistant screws on each, through the stringer first. This puts the primary grab in the new wood. Do this on one side of each stringer as needed.