Typar Drainable Wrap is a new product. I haven't seen it but I assume it would have "TYPAR DW" written on it.

Photos of it online are not consistent bit one of these should be accurate.

Its available from Amazon

Thank you for the comments.

The house wrap that the contractor used is a thin white material with “TYPAR BRING ON THE ELEMENTS” printed on it, which is a nondrainable wrap per the Typar website. The contract specified “drainable house wrap” but it did not specify which brand.

The contractor prepared the contract documents and specifications. The house wrap and siding were installed a couple of months ago. We did not specifically ask him about the house wrap substitution because we only just learned of it when we were reviewing photos of the build progress.

We will check into the local code for rainscreen design as well as LP SmartSide requirements.

Unfortunately, the siding has already been installed so it would be expensive to remedy.

The need for a drainable house wrap should be determined by the amount of rain expected rather than the cladding manufacturer's installation instruction but its worth checking.

I've been an architect in MA for 50 years and built several houses on the Cape waterfront but used Huber's zip system sheathing rather than a house wrap. Wind blown rain has been a problem for doors and windows but not the walls, however, I also used 18" triple coverage cedar shingles.

You didn't say if the SmartSide was shakes, lap siding or panel siding.

Has this contractor built on the coast before?

So called "drainable" housewraps differ from other housewraps by providing bumps creating a gap--an escape route--for water penetrating the exterior house plane.

But rather than depend on the "drainable" wraps, which were just being developed at the time, in the past I've used standard Typar under board and batten mounted on strapping providing a half-inch gap between the Typar and the b&b.

So, even if the contract was not followed, the method used may meet the objective as well or better.

I second RES's comment regarding amount of rain being the determining factor - reviewing the siding manufacturer's instructions is more about warranty implications in case of a failure - sorry if that was unclear.

If your local code includes rainscreen design requirements (accounting for amount of rainfall), the code official should be able to advise on that. If not, you could contact a local architect or building scientist for an opinion. Also, have you asked the contractor exactly how the wall was built? Since the siding is already on, it's possible the contractor used the flat wrap with another rainscreen solution such as the strapping worthy mentioned. Maybe not what you were expecting but could could be a fine solution.

I work mostly in Southern Maine, and have had similar results to RES with cedar cladding and zip system sheathing. I haven't specifically used the SmartSide products, but with true wood (as opposed to engineered wood) siding, I do prefer a larger gap than the drainable wrap provides - usually either strapping or a layer of breather fabric depending on the particular siding product.

Thanks for the comments. The SmartSide is lap siding. Based on the build progress photos (which are not all that clear), it looks like the contractor attached the siding directly to the nondrainable wrap, with no strapping or other material in between. We will try to get more information from the contractor and code official next week.

That meets LP's installation guidelines.

But it is far from best practice, may not meet your Code and certainly not your contract as you describe it.

Is this ocean-front property? If not, how far is it from the water? For houses on the ocean, painted siding doesn't last long hence the common reliance on cedar shingles and cellular PVC trim. Since the builder specified an aspen wafer board siding protected with preservatives and a painted MDO paper facing, I suspect you are out of the heavy windblown water.