Ask the Experts – November 2016

SponsoredbyLaticreteOne of the benefits NTCA offers is its technical staff, and seasoned know-how that can be tapped to address problems and questions. Here’s an example of the profusion of information from the NTCA technical staff for the questions of one Hawaiian homeowner. – Lesley Goddin


I am a homeowner in Hawaii looking at installing a large-format porcelain tile floor (planks are ~9” x ~47”). I have two questions.

My first question is what is the NTCA convention for pricing that tile install? Is the convention for an install price per square foot based on the actual footprint of the rooms (actual tile on floor when job is done) or does it also apply to the tile waste?

As an example:

– Lets say I have a simple 25’ x 40’ room: 1,000 sq. ft., once the tile is installed.

– Lets say I plan on 10% waste. So I purchase 1,100 sq. ft. of tile

Would your convention for the installers bid price be X dollars per sq. ft. based on the 1,000 sq. ft. or based on the 1,100 sq. ft.?

My second question is what sort of waste percent should I expect for that large-format 9” x 47” tile?

Thank you for your time and feedback.


We have three technical trainers on staff, and they are all coming off of extensive travel dates for training programs, so I am taking a shot here on this question, and they will likely provide additional or a slightly varied response.

In my experience on this subject, the labor bid for the job generally covers the 1,000 actual square footage of the room in the bid. However, if you have a 10% waste factor for materials, you would be charged for the 1,100 sq. ft. of material. My customers usually ordered about 3-5% in a straight-cut square pattern and 7-10% with a pattern design, like what you are describing below. This depended on room size and how it is laid out. I will see if they chime in with a different response but this has been my experience in the past.

Bart Bettiga, 

NTCA executive director

Bart has provided you correct information. I would add that with a plank tile such as your 9” x 47,” I may consider estimating upwards toward 12% depending on the pattern, obstacles, squareness of the room(s), etc. This is especially critical for special-order material to ensure it is all from the same manufacturing lot. Any remaining tile should be retained as “attic stock.”

There is not a standard pricing convention for labor. A contractor may base the labor rate on square footage, hourly or daily rates. A qualified contractor using Certified Tile Installers will be very familiar with the intricacies of installing large-format tile. Large tile is not necessarily faster or easier or less expensive to install. Additional substrate preparation is almost always required to ensure a quality installation based on tile industry standards.

The NTCA does have member contractors in Hawaii. Please search for them on our web site at:

To locate a Certified Tile Installer please search the Ceramic Tile Education Foundation at:

I hope this helps.

Mark Heinlein – CTI #1112, NTCA trainer/presenter

In my area, most installers are paid for the amount of material they use rather than the square footage that they cover. They do have to handle, cut, and dispose of that tile and usually will include it in their invoice.

As far as percentage waste to figure, two things should be considered: the layout of the area and the pattern to be installed. One single square room usually requires very little waste, while an installation with many corridor and rooms would require more.  Also a straight-lay pattern requires very little waste, while a herringbone pattern or an installation on a 45-degree would require much more. I figure somewhere between 5 and 15% waste considering all the factors just mentioned.

On a commercial project, the spec book often times calls for 5% attic stock to be left on site at completion. If that’s the case you would also want to add that on to your estimated waste amounts.

Robb Roderick, NTCA trainer/presenter