Kirk Grodske
08-21-2007, 02:22 PM
Here is an easy way for you to determine if you can do a mud bed or just take the opportunity to try one for practice. I took a 2.5 day course offered by Schluter Systems here in Anaheim Calif. I heartily recommend it to anyone who use their products.
Go to your garage and build a small shower set. Build a 4 x4 foot frame out of 2x6's. Lay it flat on the floor and shim with wood shims so it is flat(garage floors are sloped ya know). Pull diagonal lines so it is square. Screw on one sheet of 5x8 drywall. Flip it over. Set on floor. Don't worry if it is level now, but do mark the corners on the ground, so if you have to move it, you can put it back in the same place. Now rip some drywall and tack to the insides all the way around with 1 inch roofing nails. You can just start doing the deck mud in this thing there or band the side walls and corners with some Kerdi Band.
Take the Drain, and use it as a template to make two disks out of the left over drywall pieces. Glue them down to the floor in the center and to each other to make a dummy drain. It will be 1 1/4inches high. That is your lowest point in the shower. Follow the directions below and see what happens. Let me know if any of the terms or directions are unclear or can be improved. Because you have built this flat on a floor, you can't use the real drain, but that is what the stacked two circles of drywall will stand in for.
So one 2x6 for $5.00 and one sheet of drywall, for $12 bucks, a couple of bags of sand and one bag of cement, that you will use the rest of to do the real pan later. Very cheap way to practice. By tacking the drywall on with only a few roofing nails, it is easy to tear apart the dummy IF YOU TEAR IT APART BEFORE IT HAS TIME TO CURE OVER NIGHT!!
The Lesson (Note: for you 4x4 and no drain, just the drywall circles )
How to do a mortar bed mud shower pan with the Kerdi drain.
For this lesson, we will use a 4.5 foot by 4.5 foot square shower pan.
First open box and put drain on floor on the Styrofoam spacers that come in the box.
Measure from the center of the drain to the farthest point to determine your highest point bases on ¼ inch per foot. So if it is 2 feet, that is ½ inch plus the height of the drain or 1 ¼ inches. While I like to draw a line at this point around the wall to serve as a confirmation guide, since the floor is not necessarily level, this can be misleading.
Next dump some deck mud( 1 part Portland and 5 parts sand, very dry to where it just clumps if you squeeze it.) around the perimeter of the shower, about 5-6 wide and twice as high as you think you need it. Set a 2 foot level on top of your second joint of your finger while holding it on the drain and the other end on your perimeter deck mud. Pound down the level into the mud with the end of a wood float, until it reads level to the end still resting on your finger.
Remove the short level and set a 4 foot level across the divot made by the short level and parallel to the perimeter deck mud. Pound down this level with a wood float until the big level bottoms out on the divot and is level from end to end. Slide it each way until the entire side is level.
Take the long level to the next perimeter that is adjacent and pound it down until the corners are level and then along the level to level the side. Move to the next side and then the final side and you should end up back where you began and at the same level.
Then remove the level and use your steel trowel to pack and scrape the rest of the side mud to that level.
Remove the drain and the Styrofoam spacers and place wet set ( 1:3 Portland to sand and wetter, so it is still stiff but will ooze through the holes in the drain perimeter) around drain hole. Set the drain lightly into this mortar and use the short level with your finger under it while pushing the drain down until the bubble shows level. Then set a level across the drain and level top to bottom and side to side as if on a clock face. I. E. like 12 to 6, 3 to 9, and finally 2 to 8 and 4 to 10.
Distribute more deck mud all around the floor and divide the floor into 4 quarters starting with one of the quadrants away from you. Start spreading and packing the mud between the drain and the perimeter screed pack. Keep your trowel pointed so one end is to the drain and the other toward the wall. Like the hands of a clock. Never turn it perpendicular to this position and pack, as that will create divots.
Once packed, use the metal screed or box screed to scrape the mud from the drain to the screen pack until it is a smooth incline with no gaps or humps. Fill the gaps with more deck mud, pack and then scrape off. Just scrape off the humps. Take a wood float and vigorously massage(rub) the deck mud so that there is no voids and a smooth, even surface. Once the first quarter is done, do the next one away from you. This way, you won’t be putting knee marks on your finished sections and you can work toward the opening. Remember to shave down the first 5 inches of the perimeter deck mud so there isn’t a flat spot, but that is tapers gradually starting at the wall.
Once all quarters are pack, screeded and rubbed, use a steel trowel to push down all the little granules of sand into the dry pack so there won’t be a lot of crumbs when you spread the thin set and set the Kerdi.
You should be able to walk on this mud with stocking feet and leave no impression. You can tile in a couple of hours or wait until over night to insure not putting dents into it.
Good luck.
Go to your garage and build a small shower set. Build a 4 x4 foot frame out of 2x6's. Lay it flat on the floor and shim with wood shims so it is flat(garage floors are sloped ya know). Pull diagonal lines so it is square. Screw on one sheet of 5x8 drywall. Flip it over. Set on floor. Don't worry if it is level now, but do mark the corners on the ground, so if you have to move it, you can put it back in the same place. Now rip some drywall and tack to the insides all the way around with 1 inch roofing nails. You can just start doing the deck mud in this thing there or band the side walls and corners with some Kerdi Band.
Take the Drain, and use it as a template to make two disks out of the left over drywall pieces. Glue them down to the floor in the center and to each other to make a dummy drain. It will be 1 1/4inches high. That is your lowest point in the shower. Follow the directions below and see what happens. Let me know if any of the terms or directions are unclear or can be improved. Because you have built this flat on a floor, you can't use the real drain, but that is what the stacked two circles of drywall will stand in for.
So one 2x6 for $5.00 and one sheet of drywall, for $12 bucks, a couple of bags of sand and one bag of cement, that you will use the rest of to do the real pan later. Very cheap way to practice. By tacking the drywall on with only a few roofing nails, it is easy to tear apart the dummy IF YOU TEAR IT APART BEFORE IT HAS TIME TO CURE OVER NIGHT!!
The Lesson (Note: for you 4x4 and no drain, just the drywall circles )
How to do a mortar bed mud shower pan with the Kerdi drain.
For this lesson, we will use a 4.5 foot by 4.5 foot square shower pan.
First open box and put drain on floor on the Styrofoam spacers that come in the box.
Measure from the center of the drain to the farthest point to determine your highest point bases on ¼ inch per foot. So if it is 2 feet, that is ½ inch plus the height of the drain or 1 ¼ inches. While I like to draw a line at this point around the wall to serve as a confirmation guide, since the floor is not necessarily level, this can be misleading.
Next dump some deck mud( 1 part Portland and 5 parts sand, very dry to where it just clumps if you squeeze it.) around the perimeter of the shower, about 5-6 wide and twice as high as you think you need it. Set a 2 foot level on top of your second joint of your finger while holding it on the drain and the other end on your perimeter deck mud. Pound down the level into the mud with the end of a wood float, until it reads level to the end still resting on your finger.
Remove the short level and set a 4 foot level across the divot made by the short level and parallel to the perimeter deck mud. Pound down this level with a wood float until the big level bottoms out on the divot and is level from end to end. Slide it each way until the entire side is level.
Take the long level to the next perimeter that is adjacent and pound it down until the corners are level and then along the level to level the side. Move to the next side and then the final side and you should end up back where you began and at the same level.
Then remove the level and use your steel trowel to pack and scrape the rest of the side mud to that level.
Remove the drain and the Styrofoam spacers and place wet set ( 1:3 Portland to sand and wetter, so it is still stiff but will ooze through the holes in the drain perimeter) around drain hole. Set the drain lightly into this mortar and use the short level with your finger under it while pushing the drain down until the bubble shows level. Then set a level across the drain and level top to bottom and side to side as if on a clock face. I. E. like 12 to 6, 3 to 9, and finally 2 to 8 and 4 to 10.
Distribute more deck mud all around the floor and divide the floor into 4 quarters starting with one of the quadrants away from you. Start spreading and packing the mud between the drain and the perimeter screed pack. Keep your trowel pointed so one end is to the drain and the other toward the wall. Like the hands of a clock. Never turn it perpendicular to this position and pack, as that will create divots.
Once packed, use the metal screed or box screed to scrape the mud from the drain to the screen pack until it is a smooth incline with no gaps or humps. Fill the gaps with more deck mud, pack and then scrape off. Just scrape off the humps. Take a wood float and vigorously massage(rub) the deck mud so that there is no voids and a smooth, even surface. Once the first quarter is done, do the next one away from you. This way, you won’t be putting knee marks on your finished sections and you can work toward the opening. Remember to shave down the first 5 inches of the perimeter deck mud so there isn’t a flat spot, but that is tapers gradually starting at the wall.
Once all quarters are pack, screeded and rubbed, use a steel trowel to push down all the little granules of sand into the dry pack so there won’t be a lot of crumbs when you spread the thin set and set the Kerdi.
You should be able to walk on this mud with stocking feet and leave no impression. You can tile in a couple of hours or wait until over night to insure not putting dents into it.
Good luck.