LP siding or knot

This is from an inspection today. I’m pretty sure this is LP siding but onsite and now looking at pictures, the more I stare at the knot, the more I think my eyes are playing tricks on me. Any confirmation or correction would be helpful.

Any pictures of butt joints, end joints or bottom edges? Any swelling, saturation or delamination?

Compare with this Joe:


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Brian, there was no swelling or delamination. This house was renovated over the last year or so and siding is new. Here are a few more photos:

IMO, that is a composite wood siding. Some people call it hardboard. It is not cement fiber siding or sawn plank board. LP is a brand name, stay away from brand names unless you watched it come out of the package and installed in front of you or it is stamped.

Those cut edges should be painted.

In your final photo, that is OSB plywood (oriented strand board) and it is not exterior rated. It will deteriorate as installed.


Thanks Brian!

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Composite wood siding all suffer from the same problems. Installation and maintenance will determine its longevity. As Brian pointed out installation is a problem right out of the gate.


Your welcome. Good job on getting the detailed photos, the devil is always in the details when it comes to siding install which will dramatically impact long term performance.

It’s probably actually a strip of LP Smart Side. That is what the unfinished side looks like. If my bearings are correct on the orientation of the picture, it is not meant to be installed like that. At least they did paint the exposed face.

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No one can answer this question correctly. I usually take my pocket knife. And dig into it a little bit and inconspicuous area. Did you determine what it is. It could be cementitious. It is your report and if you don’t know. Educate yourself a little farther

I dunno, looks awfully thick. But, to your point…it should be corrected.

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It looks like Smart Side siding from LOWES. :thinking:


When in doubt, pull it out… :crazy_face:


T1-11 OSB siding.

I feel like the grain on T1-11 is no where near that pronounced. It is a smoother texture.

Do you guys know what makes the siding “smart”?

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This is not your father’s LP siding. The Smart Side product is actually quite durable. I have it on my house and love it.

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It is all about the install baby. I see cement fiber siding falling to pieces due to bad installs.


Definitely LP which used a OSB panel as the base coat. If it is meticulously maintained and painted it can last decades. Although sold as a lower maintenance exterior siding is still actually a high maintenance product and the lowest cost siding on the market. So you will see it on a lot of starter and low end housing. That knot repeats if you look at a larger area.

Not true at all for LP Smartside, at least in my neck of the woods. Vinyl is by far the lowest cost siding available. LP Smartside is more in line with HardiePlank fiber cement.