This is my home for the last 10 years with T1-11 installed horizontally in the front.

enter image description here

Is it "wrong" to have it like that? I am not having any water issue for a decade since. But now I am selling my house, the home inspector said it is wrong and must be re-done to pass inspection. Since he said water can collected and damage. I argued that the 2-ft overhang was good enough.


  • Is that really t1-11?
    – Kris
    May 19, 2019 at 16:31
  • 1
    I think if the buyer wants a different more durable siding he should buy a different house or reside yours on his own dime after closing. Obviously this siding and the maintenance you have kept up with has been sufficient to resist the effects of the weather in your area. Perhaps if your house was in a tropical climate it would not have faired as well.
    – Kris
    May 19, 2019 at 16:49

1 Answer 1


True, the grooves are to be installed vertically. Here is an installation sheet from LP, who manufacturer’s the siding:


If you carefully read the instructions, you will not find any instructions that say it cannot be installed with the grooves horizontal. Rather, they only show it installed vertically.

Originally, T-1-11 siding was made from standard A-C plywood with a “textured” face ply (thus the T symbol in its name) and grooves cut into the plywood along the 8’ length.

This method of making “siding” was not acceptable, because the inner plies had voids. The voids were caused by spaces between the inner plies during fabrication. This allowed moisture to lay inside the siding and cause rot.

In order to avoid this problem, they started making the inner plies “plugged”. Plugged meant they’d fill all the voids in the second and third plies so that moisture could not penetrate the siding.

Your siding must be that latter type of siding, because I do not see blistering or rot on the face of the siding. Installing the siding with the grooves vertical or horizontal doesn’t matter with the inner plies plugged. Moisture cannot enter the siding.

Btw, you must have maintained your siding by repainting on a regular (3-5 years) period. Otherwise, any siding would have deteriorated and started showing signs of rot.

Btw, who paid for the home inspector? When I sell a property, I always pay for the home inspection, because if I don’t like it, I’ll hire another, and another, and another until I get one I like. (This works the same when I buy a property too.) If you paid for the home inspection, toss it and get another inspection.

  • "In order to avoid this problem, they started making the inner plies “plugged”. Plugged meant they’d fill all the voids in the second and third plies so that moisture could not penetrate the siding." <-- Is this something I can prove as a latter type? Maybe pull off one small chunk somewhere?
    – HP.
    May 19, 2019 at 6:14
  • The buyer pays for home inspector. I believe its around $800 (not cheap) so my real estate agent advise against it in the beginning and I should not do my own. Since then I have to disclose all information (not sure if this is true but its out of the topic here).
    – HP.
    May 19, 2019 at 6:15
  • @HP. Proving the inner plies are plugged will not satisfy the home inspector. It may mitigate the situation, if the buyer decides to ignore the inspector’s report/recommendation.
    – Lee Sam
    May 19, 2019 at 7:27
  • @HP. Yes, it’s too late now for you to submit a home inspection because the buyer has already purchased it. I’ve submitted one with the listing and buyers will often accept it. It was “on topic” because you closed your original OP with the line, “Thought(s)?” My thought was to find an acceptable inspector. (I do the same with appraisers.)
    – Lee Sam
    May 19, 2019 at 7:34
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    If you think $800 is not cheap, wait until you get the bill for replacing the siding.
    – Lee Sam
    May 19, 2019 at 7:48

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