LP Smart Siding - Fire Rating?

I inspected a new construction home inside Houston today. Single family home with less than 5 feet separation to a twin house on the divided lot. The house was advertised as having cement fiberboard siding, but it turned out to be sided with LP Smart Lap Siding

For houses with less than 5 feet separation the walls are required to meet “1 hour-tested in accordance with ASTM E 119 or Walls UL 263 with exposure form both sides”

Does anyone know if LP Smart Lap Siding meets this standard? I have not found anything saying it does, but the LP customer desk is closed and don’t want to jump to conclusions. The city green tagged it, but they might well have thought it was cement fiberboard and we don’t rely on city inspectors anyway. This could be a big issue for the builder if the siding does not meet the requirement.


unless something has changed my data from lp

What is the fire rating?
LP SmartSide is a class C (III) rated product when tested according to ASTM E84. All LP SmartSide siding can be used in a 1‐hour fire rated assembly when it is installed over 5/8 type‐X gypsum, which is consistent with other siding types such as fiber cement siding.

Right Mr Adair.

The 5/8" drywall sheathing or 1hr burn rating is a requirement when 5’ or less from another building. Its been a few years since I built anything but that’s what I remember.

When have you seen Adair ever wrong, Paul.

Never heard of him till yesterday, didn’t know he was a legend around here:shock:

You have no idea…! :mrgreen:

Barry is always on the money - Thanks Barry.

I think we’re going to ask the builder to demonstrate compliance and ask them how it was installed without giving them the right answer. I’ll try to get a hold of LP tomorrow too. There is a difference in the ASTM standard referenced between the LP doc and the model code.

Wouldn’t surprise me if they shortcut the Type X requirement to save the $$$. Once it’s covered over, who’s to know?

further info…that i know you probably know ;~))
if they say/doc gypsum board was used
assure proper exterior grade was used

How it was written in the report - this is new construction:

Yes. I do cite model building codes in my reports and will continue to do so (please refrain from advice about not performing code inspections). I have spoken with the client who knows what the correct response from the builder should be (we do not want to give the builder the answer so that they can simply parrot it back). I will call LP this morning for clarification regarding the applicable ASTM test standard certification.

Read about it here…

In my area you must prove you installed the correct sheathing. It either gets inspected or some building departments will accept a photo before its covered.

Never had a problem either way.

If that’s a photo of Barry first thing I thought was he looks like the bass player for the Beet Farmers band.

The Loud and Plowed album.:cool:

Confirmed with LP about the Type-X gypsum this AM and the builder came back with the proper response for wall construction, so it’s a non-issue.

That’s Badair alright and he sounds a bit like Sam Elliot when you talk to him.