This Bottom Drain is being installed in an indoor plywood tank, but the procedure is the same for an outside concrete bedded Bottom Drain.
Start by cutting the circle out of your liner to fit the BD.
This Bottom Drain is being installed in an indoor plywood tank, but the procedure is the same for an outside concrete bedded Bottom Drain.
Start by cutting the circle out of your liner to fit the BD.
Next get some 2" finish nails and sharpen the point. Put these finish nails in every other hole, point up. This will space the liner up off the BD flange for easy adhesive application and are used as alignment pins for installing the clamping ring.
Now apply a heavy bead of P&L polyurethane roof and flashing adhesive on the BD flange. Then push the liner down over the pointed nails.
Next apply another bead of P&L on top of the liner and place the clamping ring on that, using the protruding nails as alignment pins. One by one remove a nail and put in a screw. Just tight enough to see some of the P&L squeeze out.
Now go around and hand tighten the clamping ring. Not to tight, just enough to ooze the P&L out. if you go to tight you can crack the clamping ring or strip out the screw.
Smooth out the P&L with a gloved finger. If you get any on you acetone will take it off.
Finish off by installing the dome. In most cases you will have to trim the stand pipe.
For a 3" BD flowing 15 to 2500 gph you want a half inch gap.
For a 4" BD flowing 25 to 3500 gph you want a 5/8 to 3/4 inch gap.
Nothing to it. I use the same procedure and alignment pins for doing TPR flanges.
Another fantastically useful post, Steve. I realize that this is not an extremely complicated process -- but seeing photos of it performed step-by-step, with all the useful narration and helpful hints, really makes it seem easy. Thanks very much for going to the trouble.
Paul
Steve,
Since you posted this and the fact that I'll be installing my liner this weekend, I have a couple of questions.
My pond is an irregular shape.
I already have the bottom drain concreted in and I laid the underlayment tonight.
I am worried that I cut the liner, install the drain like described and start filling, the liner pulls and stresses that connection at the bottom drain.
I would not be as worried if I had a square block pond. It would be easier to predict and lay the liner down. Since I am in a kidney shape with shelves etc. That the liner will pull when filled with water. I went what I think is overkill on the size of the liner and I'm probably just worried for nothing.....
Any tips?
Jerry
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Thanks for the post, Steve. Very informative pictures and descriptions.
I am also installing an odd shaped pond. What I was thinking of doing was to provide a lot of slack liner along the top edge of the pond (sitting on the concrete collar). This way, when/if the liner tries to stretch and pull, it will take up the slack from the liner at the top, not at the bottom near the BD.
Great post Steve!
The idea to use the nails as alignment pins really makes this an easy task.
Two thumbs up... WAY UP!
I too will be installing my liner hopefully next week. It makes me nervous to think about cutting holes in my liner, but your demonstration has answered some of the questions I had. I will have two bottom drains, and plan on leaving just a bit of slack in between the two BD, just in case it does want to pull.
zack
Steve, if someone is going to also have an underlayment below the liner, that would go under the lip of the BD collar, right? Or, I suppose one could just trim the underlayment around the outside of the collar and leave it at that?
Great thread Steve
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Steve,
I wish I would have seen this thread last year before I installed my 4 bottom drains it would have made lining up the screw holes much easier. But I must have done it right because they have been installed for a year and no leaks. A very helpful post for those installing a bottom drain. Thanks again Steve for all of the useful information that you post in this forum.
Larry
I so needed to see that, I have had to have thearpy over this proceedure and I have not even started my pond yet. ha ha
Great post. Thanks for sharing.