For Want of a Squash Block

[hausdok]

By JD Grewell

This tale brings to mind the old saw: ‘for want of the nail, a shoe was lost; for want of a shoe, the horse was lost; for want of the horse, the rider was lost; for want of the rider, the battle was lost; for want of the battle the kingdom was lost, and all for the want of a nail.’

As a contracted Dispute Settler for the Montgomery County (Maryland) New Homes Warranty Program, I was assigned to investigate complaints on a large, expensive new home.

The complaint list included squeaky subflooring in the master bedroom suite, a stiff door off the suite, a leak above the sunroom, and hairline cracks to a pass-through and in 14" x 14" ceramic floor tiles in the kitchen and sunroom.

The builder claimed the house was built per the plans, with only the substitution of TJI wood I-joists for Georgia Pacific’s joists, with the 2" x 14" joists set on the 19.2- inch-centers. He said the squeaking subfloor was normal, and silicone caulking was the answer to the ceiling leak. The hairline cracks in the tile had to be the manufacturer’s fault because it was installed with Durock underlayment on approved OSB subflooring.

Because I could see a steel girder without squash blocks or blocking panels below a loaded wall, I asked a Consumer Affairs official at the site to have the local TJI structural engineer do the following: confirm squash blocks were needed; check the floor loads; and to determine appropriate stiffness required for ceramic flooring.

The engineer reported that blocking panels or squash blocks were needed and that the floor stiffness was appropriate for ceramic tiles. After reviewing the plans, he echoed my concerns about the lack of access to a second steel girder below the kitchen and sunroom that was closed in as part of the finished basement. Even though the builder claimed he had installed squash blocks with this girder, the owner agreed to open the basement ceiling at random points, as well as remove the ceramic tiles and underlayment on the floor above to expose the subflooring.

Once the critical areas were exposed, the builder’s foreman, the homeowner and I took a look, first at the tile floor. The Durock had been laid parallel to the subfloor – counter to what is required. The ceramic tile fractures were centered along the subfloor joints. Seemed like a closed case until I noticed that the subfloor sloped.

On the same wall as the passageway between the sunroom and the kitchen, there was a pass-through above the kitchen sink and countertop opening into the sunroom. Encased 4" x 4" posts supported the headers above these wall openings. The posts at the doorway were sinking into the subfloor showing compression. By using a spirit level I could see the floor had dropped 1.5". Then I saw one-inch diameter holes drilled through the subfloor in the kitchen around this doorway.

Why the holes? The owner said they had been drilled when he expressed concern about damage to the OSB from the rainwater that pooled in this area during construction. The holes let the water drain harmlessly to the basement. Good enough, but why the compression and now sloping floor?

We traipsed to the basement. With the ceiling open, we could see there were no squash blocks between the wood I-joists, and we could see the outline of the doorposts. The posts were installed atop the bays of the joists without blocking to transfer the floor and wall (point) loads down to the girder, hence the compression and sinking of the subfloor.

The foreman claimed the house was built to the plans, therefore this was the fault of the architect hired by the owner. We reviewed the owner’s copy of the plans. The foreman pointed out where the posts where shown landing between the joists and without blocking. I turned to the detail page and showed him a specific detail marked as “typicalâ€

[monte]

Mike

Nice report. A lot of Foreman's never look at a detail drawing.

[hausdok]

Yes,

Thanks to J.D. and ASHI for sharing.

Mike