Last Saturday I worked with my buddy prepping his daughter's bathroom floor for tile. There where a lot of upgrades to the bathrooms design and to cover the original sheathing we decided to go with a 1/4" layer of Wonder Board Lite. To install the Wonder Board I used Laticrete's 254 thin-set. We used 1.5" roofing nails (galvanized and a wack of them) and then tapped the seams of the boards with 4" mesh tape and more Laticrete 254.
Over this will go a Nu Heat Pad and some minor levelling....
The key points to this style of install is keeping the nails from hitting the floor joists below. Also keeping the board from bonding to the sides or bottom plates and tub are key. We kept everything back a good 1/4" to be safe.
Here you see me a few days later and I have just wiped the wonderboard lite down (after I vacuumed). Once the floor was clean and free of all debris I layout out the heating mat and cleaned both sides of this as well. Later I set it over the tub to dry. I do not want standing water anywhere - not on the mat and not one the floor.
After this was done I mixed up some Laticrete 254 thin-set. To make the mix looser I added 20% more water than spec'd. Laticrete 254 is not a low end thin-set. The choice of this premium setting material is because you do need to make a thin-set mix loose. So a great strong thin-set is still good when weakened by this over watering step. I have measure the strength of laticrete 254 in shear tests at this miz ration and the results are impressive. You can learn more about shear testing here:
Set tight to the Wonderboard Lite Sub Floor. I'll be back this weekend to cover this floor with a layer of Strata Mat and do some minor levelling for the small mosaic tile.
Last edited by johnfrwhipple; 11-30-2013 at 08:09 AM.