The hardwood floor is going in this week, so I started to lay down the Hardibacker board for the tile floors. There will be tile in the bathrooms (3), kitchen, and mudroom, about 600 square feet in total. In order for the tile and flooring to come out flush, we needed to use the 1/2" (0.41") backer board. I bought 45 sheets of the 3' x 5' board at Home Depot last week and brought them home in our little 1000-lb capacity trailer. I was guessing that the board weighed 15-20 pounds each, so that meant the payload would be 700-900 pounds. No problemo.[P.S. There is un problemo. I thought the kitchen tile was 1/4", but the hardwood guys say floor tile is 3/8", so I should have used 1/4" backer board. Oh well. The flooring guys will make thresholds for the two places where there are transistions (master bath to master bedroom, and guest bath to great room floor. I can return the remaining 1/2" Hardibacker board for 1/4" so there won't be any elevation changes from the kitchen tile. I can live with this.)
Well, after the HD guys loaded the board, the tires were pretty low. Went over to Costco, which is always the second stop on our trips to Sequim. The guys at the Tire Dept. pumped up the tires from 20# to 55#, and noticed that one of the lug nuts was almost off. Looks like I should have been doing some maintenance on the trailer, in advance. They torqued all the nuts, we did a visual on the lights and all was well. The load trailered nicely on the 25 mile trip home. However, when I looked up the specs on the Hardibacker board for installation, I noticed that they weight about 40# each. So the real payload was about 1800 pounds, plus another 80 pounds of paint (2-5 gal buckets). I guess I'm lucky I got it all back to Port Townsend in one piece.
I started the tile backing board project by laying out the sheets, as efficiently as possible on the floors. You don't want any four-way corners as they are weak points, so you need to stagger boards. I cut and laid out all of the board board in a half day, which seemed pretty fast. This even included cutting two sheets with circular holes for the toilets. The fastest way to cut these holes is with a Sawzall and narrow blade. 30 seconds and you're done. As for cutting the board, Hardi Corp suggest using a carbide bladed knife to score the board, then breaking it. That might work well for the 1/4" stuff, but not the 1/2" board. I resorted to my battery powered circular saw with a carbide bit. It throws off a lot of dust, but its only Portland cement and sand so a dust mask is advised.
Today I started the more time consuming job of cementing and screwing the boards in place. Since the under layment is Warmboard, with the vulnerable pressurized-Pex tubes right there, you have to map out their routes and trace them on the top of the Hardiboard. This was pretty easy since you have a 1/8"-1/4" gap between the boards which exposes the Pex. After tracing all the Pex routes, I took up one board at a time, applied a thin coat of modified thin-set mortar with a 1/4" notched trowel and put the board back in place. Walk all over it, slide it back and forth, and she's pretty well bedded. Then its screwed in place with 1 1/2" square bit drywall screws on 8" centers. It took about 6 hours to lay 8 sheets of board, which works out to 10 sheets per day. It takes one 50 pound bag of mortar to do 5 sheets, for a coverage rate of 75 sq. ft per bag. Most of the mudroom is just rectangular pieces so that will go faster, whereas the guest bath is irregularly shaped and has a toilet. Nevertheless, I should finish the those areas in an other day, then one for the kitchen (later) and another for the upstairs bath (much later). Tiling will be much slower since it involved cutting a myriad of tiles, and grouting. I won't actually tile any area until the adjacent cabinets are installed.On Tuesday, the hardwood installers are coming over to lay the job out, and perhaps nail a few in. That's another blog for another day.
