Buying a 10yo home FSBO, owner was the builder. Owner says the wavy floor on the 2nd storey is from the roof not being on before they did the 2nd storey subfloor (OSB, 2000sqft) and several rainstorms damaging the subfloor.
It is probably up/down waves of 3/4"+ across several rooms... so it is a general problem.
It is finished in $10/sqft brazillian walnut (!? = $20k I. Brazillian walnut over wavy floors... ugh).
BUT looking closer the sags are not in the 16" between joist spacing, but both directions and 3 or 4 feet between "peaks". Wife is BENT on buying this house. Why would these floors be so wavy? No visible foundation settling evidence (no drywall cracks, etc).

I first believed the owners story, but seeing the dips are not fitting in the space between joists... I am suspicious.

Votes for any of the following reasons?

Shoddy joist install where they are not level and square to each other? (Note, first floor is level)

Termites? (Note, first floor is level, no bounce in the floor is felt and no visible evidence, but we are in a termite area)

The owners story of weathered 2nd storey decking?


We are still in our inspection period. Who do we have look at it to say one way or the other?

  • You should walk (maybe even run) away from this deal. No reputable builder would be trying to pawn off the sale of a house with a floor such as you describe. Especially with a lame sounding story like that.
    – Michael Karas
    Commented Jan 21, 2017 at 19:17

1 Answer 1


no builder in his right mind would have installed hardwood on a wavy floor. it sounds more to me like their was a flood which has damaged the hardwood. its swelling, subsequent twisting and then drying has caused the randomly warped floor, but it could also be too high of an ambient humidity, which can be a sign of a bad vapour barrier system and all the nightmares that come with that.

just get a certified engineer to write it up, or even better, just run away as fast as you can (unless you are getting some ridiculously good deal on it). remember, many builders are shysters at heart, so other things could be wrong that are currently hidden.

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