Glass Thickness - Viewing Windows For Pond Built Above Ground
  • khongkhong April 2011
    Posts: 144
    Hi All,

    I am building a concrete pond with a glass viewing window at the front side. In the other words, 3 sides of the pond is built by reinforced concrete and the front site will be with concrete and glass.

    The total pond size is 13' (L) * 10' (W). The depth (D) of the pond is 3.5', which 1.5' is below ground level, and the other 2' is above group level.

    I plan to use a piece of the tempered glass with size of 8' (L) * 2' (H) as the viewing window. Both end of the glass will be supported by concrete wall of about 2.5' in length. Which is the suitable thickness of the glass I shoud use? Is 12mm thickness good enough?

    Since part of the pond is underground and the glass viewing window is above the group level, what is the depth I should use to calculate the water pressure on the glass?

    p/s my initial plan is to build the pond below ground but last minute changed my mind. The digging work started today.
  • ChengAunChengAun April 2011
    Posts: 925
    Hi, most of us don't use glass panels but we sure wish to! i think 12mm may not be thick enough. perhaps maybe 15mm may be better :) what filtration do you intend to use? be sure to add bottom drains (preferably 2) at one end of the pond and the water returns from the filter on the opposite end. Dont make the same mistake that i made of not adding btoom drains :)
    Be updated in the world of koi. Jangankan seperti "Koi di bawah bottom drain"
  • PH8PH8 April 2011
    Posts: 683
    I think we will need the input of our Kuching brothers here. Quite a number of ponds there have side windows, but I have personally not seen one in KL yet. Maybe Bro Alan could help here... :)
  • heng84heng84 April 2011
    Posts: 77
    i think people use laminate glass instead of tempered?? not sure though cos mine is use for skylight roof, 10mm thick.. 5+5 reason of laminate if u drop something on it.. it crack and still got 2nd layer to support u wont drop.. if tempered.. u drop something and it shatters and u fall into the pond :P personally they test for me how solid the glass is by 3 average 70kgs people standing on a piece of glass 4feet x 6feet so if u want safer go for thicker one .. i dont stand on it so i use 10mm oni haha.. better go for much thicker ones
  • yysim88yysim88 April 2011
    Posts: 340
    Hi, just checked with Bro Yap of Kuching and was told that he used 19mm tempered glass with stainless steel frame sealed with silicon gel.

    According to Bro Yap, it is important to have the steel frame as silicon gel does not stick to cement well and will come off over time. The steel frame is casted into the cement wall and is infilled with silicon gel before the tempered glass is inserted and any visible gaps will be filled with silicon gel again. Any excess silicon gel that sticks to the glass ought to be removed before they fully harden.

    According to Bro Yap, his is functioning well without leakage which is the biggest fear in having a "TV screen" for the pond.

    If you need further details, pm me and I will get you in touch with Bro. Yap.
  • khongkhong April 2011
    Posts: 144
    Dear All: thanks for the reply.

    ChengAun: Thanks for reply. My pond design is with bottom drain. You actually replied to my other post at http://www.koianswers.com/discussion/533/buidling-new-pond-in-puchong-need-advice/#Item_3.

    Bro heng82: I think your glass is like the platform on top of the pond. Mine will be at the site of the pond and serve as a "window" to see the inside of the pond. I will look for more details for laminated glass. thanks for advice.

  • heng84heng84 April 2011
    Posts: 77
    oh sorry my bad.. didnt read properly.. its side view for the pond i tot u wanna stand on top of it.. haha
  • hsleehslee April 2011
    Posts: 49
    khong, be very careful on the type of sealant that you are planning to use, i've been through a terrible experience with the leakage along the glass sealant after five years of normal operation.
    If your glass panel is build right to the bottom of the pond, when leakage happened, you will basically have to drain off the whole pond for repair, on the other hand, water pressure increases over the deep of the water, therefore the deeper your glass panel is, a thinker glass panel will need to be used and stronger sealant is also needed. Therefore, I would suggest that your glass panel is only covering half of the pond height for the ease of maintenance.
    As for the type of sealant, I have tried at least five different brands during my repair, from silicone sealant to adhesive sealant, and the one that gave the best result is 3M 5200 (marine type), is not listed as 'fish-safe' sealant, but my koi are swimming happily in my pond.
    Good luck.....
  • ChengAunChengAun April 2011
    Posts: 925
    Oh that's right. Sorry. Forgetfull lah
    Be updated in the world of koi. Jangankan seperti "Koi di bawah bottom drain"
  • heng84heng84 April 2011
    Posts: 77
    How regularly you need to scrub the glass from algae build up?
  • PH8PH8 April 2011
    Posts: 683
    It really depends on your set up. Some people hardly have any algae in their ponds whereas others have lots of algae.
  • khongkhong April 2011
    Posts: 144
    Spoke to Bro Yap of Sarawak this afternoon. Thanks a lot for Bro Yap's advice and I have better understanding now. Will make sure my contractor does the necessary.

    Cheers!
  • ElliotElliot May 2012
    Posts: 4
    Hi There all.

    First time as member and I highly appreciate if advises can be shared to solve my fear of keeping my newly built but damaged cement fish pond with front glass windows.

    The pond size is 9'x5'x3' (LxHxW) for all 3 sides cements and bottom of the pond as well except the front site was standard glass at size 9'x3' using thickness 12mm.

    Sad to share that the glass broke into pieces after filtering pump started for about 1 hours with max. water level of approx 33". The was really scary memory but lucky enough no one is hurt as the broken glasses ......

    I think 12mm T glass should be OK as the same answer from the glass supplier.

    Now that adjusted the high front panel with the cement wall into 1' above the bottom of the pond and put in new glass panel on it with size 9'x3' but using 20mm T glass but still standard glass type. This should be safe enough to the water pressure at 2' high glass.

    However, I am still worry about the way the glass fit into the cement wall. Can any one provide clear procedures and steps of how to lay the metal frame - I think of u-shape Al frame . Is it OK??? and then just fix the glass into the u-shape frame and fill with 3M 5200 sealant.

    How about the edge bonding of the glass and the cement wall??
    Also how about adding a frame on top of the 1' T glass to "HOLD" it just the standard full glass tank we commonly see on market...??

    Too many concern as I can't imaging what would happen if the glass breaks with the huge waters plus fishes flushing out from the pond into my study room as the front glass panel is facing just next to my lazy chair. Ha ha
  • wongyengwongyeng May 2012
    Posts: 238
    It is a fantastic idea provided that you make sure that you have proper protections against algae and maintenance may be an issue... but it is a cool idea ! All the best !
  • ElliotElliot May 2012
    Posts: 4
    Thanks for your comment on my ideal.

    However, I might abandon this ideal and re-do the pond into normal standard ground pond for Koi if I don't have enough solid safety features to save guard myself and my family whom will be in the same room watch TV but at slightly few foots away from my lazy chair la.

    This is my biggest concern to proceed.

    Really highly appreciate for advises from those experiences gurus and owners.

    I am not so concern about algae/maintenance as the solution of mine would be just more execises for me daily or once every 2 days. smiles!!
  • cookcpucookcpu May 2012
    Posts: 462
    Don't have a pond with a glass window. But if I remember correctly during my search on constructing a pond.

    For glass window inside a pond, the thicker the better, I think should be around 1 to 2 inch thick. IMHO.

    Reason should be water pressure and prevent koi suddenly whack their tail on the glass window.
  • khongkhong May 2012
    Posts: 144
    Hi Elliot,

    Mine is built with 15mm T glass, the glass is 2 feet above grond and the water level from glass level is about 18". My pond is slight more than 3 feet in depth, about 18 inches below ground.

    For 2 feet of water pressure on the glass, 19mm T glass should be sufficient, check out http://www.theaquatools.com/building-your-aquarium.

    Regarding the frame, mine is aluminium frame, initially I faced water leakage issue, then I sealed it with Sika silicon, which is meant for swimming pool usage and it fixed the issue.

    My humble opinion is that you have to make sure that you have a good sealant between the aluminium frame and the cement part and of course between the aluminium frame and the grass.

    The 3M product is good as well. Wish you good luck.
  • ElliotElliot May 2012
    Posts: 4
    Thanks for your valuable sharing. I will check out th sealant supplier for Sika silicon and compare with 3M.

    However since I am new member, I just got to know that we need a sealant for the aluminium frame and the cement part. This is something I need to discuss with my contractor. He is digging a U-channel on side and top of the cement wall to lay the Al frame inside by filling in water proof cement.

    See how he explained if this good enough to prevent leaking.

    Nevertheless, at least I got he proven with the glass/ mounting mechanism example to confirm 20mm T standard glass is SAFE!! Million Thanks for your advise.
  • KekwaKekwa May 2012
    Posts: 261
    Might as well use the money for the glass to boost up your filter. Side view koi no point lah, unless you are intending to keep aros
  • MikeMike May 2012
    Posts: 346
    Khong and guys,

    Hope this help. My pond have three pieces of 4' by 4' glass on the top of my pond. The glass that I use is 15mm laminated tempered glass (total thinkness of a single piece is 32mm). I have tested the strength of the glass with 5 person measured at +- 400kg standing on a single piece and it is holding. Special thanks to my gungho friends that is willing to participate on the test.

    www.koianswers.com/discussion/download/6716/Pond.JPG

    Cheers
    Michael
    Post edited by Mike at 2012-05-05 03:02:11 am
    Attachments
    Pond.JPG 57K
  • khongkhong May 2012
    Posts: 144
    Obviously side view is not meant for koi, but it just provides another view / dimension :)

    I guess one of the advantage is that the owner can have quite a good view on the koi body, without netting the koi out from the pond.

    Cheers!
  • ElliotElliot May 2012
    Posts: 4
    Thanks for sharing the type of sealant Sika. I tried seaching the product but failed as there are many type of sika sealant.

    May I know the model of the Sika sealant you mentioned that you used to bond the Aluminium Frame to the cement/concrete wall.
  • wongyengwongyeng May 2012
    Posts: 238
    Very nice Michael :D
  • khongkhong May 2012
    Posts: 144
    Hi Elliot,
    you may refer to http://mys.sika.com/en/solutions_products/02/02a008/02a008100/02a008108.html

    Products for Swimming Pools
    SikasilĀ®-Pool

    Sikasil-Pool is a 1-part neutral curing silicone sealant for use in swimming pools and permanently wet areas

    Close Details Use
    SikasilĀ®-Pool is suitable for joints in and around swimming pools, areas under permanent water immersion and frequently wet areas, such as shower rooms in sports halls or leisure facilities, between ceramics, tiles, concrete, glass, metals and other typical building substrates, etc.

    Characteristics and Advantages
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    Non-corrosive
    High elasticity and flexibility
    Colour
    White, grey and transparent
    Packaging
    300 ml cartridges, 12 cartridges per box

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