How To Install A Bottom Drain

[birdman]

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.

[birdman]

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.

[birdman]

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.

[birdman]

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.

[birdman]

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.

[birdman]

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.

[Paultergeist]

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

[Sp00ks]

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?

[TheCrow1994]

Thanks for the post, Steve. Very informative pictures and descriptions. :clap:

[Hi Utsuri]

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 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.

[Hi Utsuri]

Great post Steve!

The idea to use the nails as alignment pins really makes this an easy task.

Two thumbs up... WAY UP! :cool: :cool:

[zack67360]

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

[Hi Utsuri]

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?

[birdman]

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.
That's about it. You have to attach the BD before filling so just keep slack in the liner so it can settle from the sides.

[birdman]

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?
Yes you probably am. But we all do 1st time. Look at post 10 and 14.

[Noahsnana]

Great thread Steve :wtg:

[yorkie]

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?

I tucked the liner under the lip of the bottom drain when I installed them in my pond. It seems to have worked well for me.

Larry;)

[yorkie]

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

[tarquin13]

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:harhar:

[phoman]

Great post. Thanks for sharing.

[vipldy]

Very needed thread Thank you Steve..I will make this a sticky if that's ok with you all..:)

[mudcatslim]

Yes do, a common sense approach. But unfortunantely the good ideas are never there when I need them. Good post. Thanks.

[birdman]

Very needed thread Thank you Steve..I will make this a sticky if that's ok with you all..:)
Please do, thanks.

[six6guy]

Great thread Steve.

I recently picked up a fiberglass tank with the intention of using as my QT. Here is info on the tank. http://www.koiphen.com/forums/showthread.php?t=100210 It doesn't have any plumbing holes as yet. Anyway, I'd like to have a 3" aerated BD for the tank and I don't have any of the plumbing parts yet. So I'm pretty open to what is going to work best here. Truth be told, I'm actually in Singapore today (returning tomorrow) and still getting my mind around how I get this done.

Thinking of making a 2x6 framed stand, kinda like floor rafters with plywood on top. Then I somehow need to drill the correct size hole, and then add and seal the aerated BD. I really don't know if I can use a rubber seal for the BD or rubber seal with P&L or if I have to use fiberglass resin to seal the part into place.

Any help on how you would approach a fiberglass application would be helpful.


Thanks in advance

Brad

[Kent Wallace]

Use the polyurethane sealant!!! No gasket.

[ardot]

With regards to bottom drains, what are the pros and cons of having a vertical discharge bottom drain vs a horizontal disharge bottom drain? Is one better than the other quality or performance-wise or is it just about the installation?
Thanks

[shanet]

Sorry to bump a old thread but the manufacture website shows that PL Roofing cement to not be reccomended for underwater use. Is this the stuff you suggestes: http://www.loctiteproducts.com/p/pl_seal_rf/overview/Loctite-PL-Polyurethane-Roof-&-Flashing-Sealant.htm
Thank you!
shane

[Sp00ks]

Shane,

That looks like the stuff. I have built two ponds and used that for bottom drains, skimmers and gpr/tpr's No leaks yet.

[shanet]

Thank you ;)
Shane