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  1. #1

    Winter cover prep

    Hi looking to cover pond this year and is it better to have a cover close to the top of the pond or as I have an above ground pond with a roof , would it be just as affective enclosing the sides to keep the wind and elements off .
    Looking to use thick polollythene,

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  2. #2
    Senior Member Rank = Yonsai jphamill's Avatar
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    Hi,

    In an out door environment a close fit cover will be more efficient.

    Firstly, because the volume of air between the water and cover that is being heated is smaller and calmer and in itself will present a smaller surface area to the outside world to lose radiant heat to. Acting as a blanket if you have a reasonable insulating cover like multicell polycarbonate.

    Secondly, the loss of heat to drafts is also less assuming a decent fit.

    With a high cover you are able to go inside and enjoy more but it will have drafts and the high thin sides/ roof will lose heat promptly

    I'm in exactly the same position and have been debating the options but realise that unless its a weatherproof structure a decent lid is going to be best ( and boring)

    Jim

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  4. #3
    Quote Originally Posted by jphamill View Post
    Hi,

    In an out door environment a close fit cover will be more efficient.

    Firstly, because the volume of air between the water and cover that is being heated is smaller and calmer and in itself will present a smaller surface area to the outside world to lose radiant heat to. Acting as a blanket if you have a reasonable insulating cover like multicell polycarbonate.

    Secondly, the loss of heat to drafts is also less assuming a decent fit.

    With a high cover you are able to go inside and enjoy more but it will have drafts and the high thin sides/ roof will lose heat promptly

    I'm in exactly the same position and have been debating the options but realise that unless its a weatherproof structure a decent lid is going to be best ( and boring)

    Jim

    Sent from my SM-G973F using Tapatalk
    Thanks will go looking for pice for pollycarb 16mm be the minimum I should look for ?

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  5. #4
    Quote Originally Posted by jphamill View Post
    Hi,

    In an out door environment a close fit cover will be more efficient.

    Firstly, because the volume of air between the water and cover that is being heated is smaller and calmer and in itself will present a smaller surface area to the outside world to lose radiant heat to. Acting as a blanket if you have a reasonable insulating cover like multicell polycarbonate.

    Secondly, the loss of heat to drafts is also less assuming a decent fit.

    With a high cover you are able to go inside and enjoy more but it will have drafts and the high thin sides/ roof will lose heat promptly

    I'm in exactly the same position and have been debating the options but realise that unless its a weatherproof structure a decent lid is going to be best ( and boring)

    Jim

    Sent from my SM-G973F using Tapatalk
    Do u think 2 layers of 10mm twin wall polycarbonate either side of a wooden frame would be better than a single sheet of 16mm multi wall polycarbonate??

    Sent from my SM-G988B using Tapatalk

  6. #5
    Senior Member Rank = Yonsai jphamill's Avatar
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    Quote Originally Posted by alex1968 View Post
    Thanks will go looking for pice for pollycarb 16mm be the minimum I should look for ?

    Sent from my SM-A715F using Tapatalk
    I recently roofed an aviary for my sons finches in 25mm.
    A 3m×1m sheet of 25mm 5 cell( also called 7 wall) was £90
    The 16mm 3 cell ( 5 wall)was £80 a sheet.
    That was from a plastics supplier here in Ireland. It was about the same price on the mainland but that included mainland delivery but not over to me ! I looked at roofing megastore, but was going to get hit with bit carriage charges.

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    Senior Member Rank = Yonsai jphamill's Avatar
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    Quote Originally Posted by Ashy View Post
    Do u think 2 layers of 10mm twin wall polycarbonate either side of a wooden frame would be better than a single sheet of 16mm multi wall polycarbonate??

    Sent from my SM-G988B using Tapatalk
    Do you mean like making a type of home made glazing unit ?
    The more layers of "still"air you trap the better the insulation or "r value" will be.

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    Senior Member Rank = Yonsai jphamill's Avatar
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    Quote Originally Posted by jphamill View Post
    Do you mean like making a type of home made glazing unit ?
    The more layers of "still"air you trap the better the insulation or "r value" will be.

    Sent from my SM-G973F using Tapatalk
    As long as the layers aren't too thick 12 mm is what standard glazing units are generally.

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  10. #8
    Yeah so thinking a sheet of 10mm twin wall, then some 18mm batten around the outside edge then another layer of twin wall thus almost creating an air gap. Although it won't be air tight like double glazing...do u think thats worth it? Or just a single sheet of 16mm multiwall. Price wise it works out similar as the twin walls alot cheaper

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    Last edited by Ashy; 11-09-2020 at 01:14 PM.

  11. #9
    Senior Member Rank = Yonsai jphamill's Avatar
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    Quote Originally Posted by Ashy View Post
    Yeah so thinking a sheet of 10mm twin wall, then some 18mm batten around the outside edge then another layer of twin wall thus almost creating an air gap. Although it won't be air tight like double glazing...do u think thats worth it? Or just a single sheet of 16mm multiwall. Price wise it works out similar as the twin walls alot cheaper

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    I'd say the thermal difference between them would be very little to be honest and then there is the ease and rigidity of the 16. It has ro be manageable robust and easy to store away
    Dust tape the open edges and it will stay clean and dry in the cells.

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  13. #10
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    The following is just my personal opinion:

    Given you have a structure that it would be relatively easy to add sheets to above the pond, in your shoes I would seriously think about making removable panels to enclose your pergola.

    Reasons why I favour that over covering the pond close to the surface:

    - easier to check on fish over the winter. Problems can easily develop under covers and be missed. Covers have caused people to miss pH crashes for example until it was too late. If you have a window then this point doesn’t apply so much.

    - koi are frankly suicidal, and if they can bash themselves up on the underside of covers and their frames then they will do. It’s just how they are

    - if you have an auto feeder then it can still operate within a boxed in pergola construction. You will probably want to cover before you stop feeding, and restart feeding in the spring before removing the covers

    - you can still enjoy your fish and watch them feed if you make a hinged ‘door’ in it. Can still do that to an extent with close fitting covers, but you won’t see all of the water surface and get a good look at all of the fish in the pond and their behaviour

    - greater volume of air ‘trapped’ above water surface less likely to cause oxygen issues, particularly in a power cut when air pumps go off

    Disadvantages will be needing more square footage of polycarbonate for the job, potential for wind to be an issue if we get bad storms.

    The mode of action of covers is mostly to stop heat loss into air at the water surface, which they do by preventing that ‘warmed’ air being constantly replaced by new colder air. Raised covers can do that just as effectively as close covers if they are a good fit. Bear in mind that some ventilation is always needed even if it’s just a few narrow slits.

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  15. #11
    If it’s too thin it will need some sturdy support to prevent sagging. I went for 35mm and it works a treat!

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    Senior Member Rank = Adult Champion Twhitenosugar's Avatar
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    I use 5 panels of 10mm bronze poly carb as winter covers - not really out of choice but when I ordered the poly carb sheets for the pergola roof, they sent the wrong sized panels - result. A nice little freebie. So ended up using them to make winter covers.

    Providing there's not too much of a span, you shouldn't get any sag - even with 10mm panels.

    To make them I got bits of 2" × 2" wood and made rectangular frames. Mine are roughly around 2.5m x 80cm.

    I opted for more, but smaller panels. Rather than a few big ones. This was mainly so they can be easily stored down the back of the pond out of sight when not in use. I'd definitely have a think about how/where you can store them when working out your design.

    I made them so that they just fit within the coping stones and sit on the top edge of the fibreglass pond lining.

    This was ideal as there's 6" air gap underneath, plus air exchange can happen all around the edges as they are far from air tight.. But also butted up next to the copings means theres no chance for strong winds to get under them and lift them up.

    I used large quadrant wooden dowel/beading tacked on the inside edge of the frames to make a small shelf for the poly carb to sit on.

    Then slapped on some ducks back wood paint on the wood. And finally sealed the end of each panel with some frame sealant - mainly so the panels don't pop out of the frames.

    And the jobs a good un. Winter cover prep



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    13,000L fibreglassed raised pond with window

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  19. #13
    Senior Member Rank = Adult Champion Mikeh83's Avatar
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    I agree with feline. Enclosing the pergola would be the best solution albeit more expensive


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    +1. Koi ponds can be twelve months not just 7 �� much better to enclose the pond if possible
    Fibreglassed/5000 gals/4.5 m Tunnel/Spindrifter/Twin drums/Bio chambers/Beads/Showers/Remora ASHP

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  23. #15
    As I doubt very much I'll have fish in my new build this year. I'm not going to cover it, or is that a bad idea? As alot of leaves ect will blow into it..Winter cover prep
    Maybe I'll put some netting over to stop the vast majority of debris from going in.
    That gives me all next year to decide on how to cover for winter 2021 Winter cover prep

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  25. #16
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    Quote Originally Posted by jayjt29 View Post
    As I doubt very much I'll have fish in my new build this year. I'm not going to cover it, or is that a bad idea? As alot of leaves ect will blow into it..Winter cover prep
    Maybe I'll put some netting over to stop the vast majority of debris from going in.
    That gives me all next year to decide on how to cover for winter 2021 Winter cover prep

    Sent from my CLT-L09 using Tapatalk
    Yeah I would not bother to cover (or heat) if there’s nobody at home in the pond

    To be honest I got away with not covering at all last winter. I had a disc in my spine degenerate and was too out of action to bother with the covers, but we didn’t really get a winter as such. Only one frost and my geraniums didn’t even die in the garden. Probably wasted some power heating only to have it disappear into thin air, literally. Any badness occurring in electricity bill went unnoticed though as we have electric cars and solar panels on the house so would only be a ‘blip’ in the grand scheme of things

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  27. #17
    Cheers, I won't bother then. Was abit concerned with all the leaves etc.. but I'm basing that on the small wild life pond I have, well puddle really! I guess this one's raised has a roof and the back is getting semi clad, so should protect it some what. Not to mention the skimmer n sieve!

    Winter cover prep Heating Winter cover prep.... Nope Winter cover prep not yet, would definatley not get planning permission Winter cover prepWinter cover prep
    Jay

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  29. #18
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    Quote Originally Posted by jayjt29 View Post
    Cheers, I won't bother then. Was abit concerned with all the leaves etc.. but I'm basing that on the small wild life pond I have, well puddle really! I guess this one's raised has a roof and the back is getting semi clad, so should protect it some what. Not to mention the skimmer n sieve!

    Winter cover prep Heating Winter cover prep.... Nope Winter cover prep not yet, would definatley not get planning permission Winter cover prepWinter cover prep
    Jay

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    Yeah if your skimmer works well leaves shouldn’t be a massive issue, A good chance to check it’s working well
    I have once had a bunch of very large leaves get stuck in my skimmer pipe after a storm one autumn. But regular leaves should be copable with.

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  31. #19
    Senior Member Rank = Adult Champion Mikeh83's Avatar
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    Winter cover prep

    Removed post

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    Senior Member Rank = Mature Champion smartin's Avatar
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    Just my pennies worth, 35mm polycarb is strong and will stand up to to some serious winds that we get from time to time as opposed anything thinner, making side panels to fit in between you pergola to stop the wind chill will be challenging, upright side panels are going to get a battering from the wind and potentially weaken your Pergola and its attachment to the pond overtime, most of us opted for the easier option of panels spanning the pond and for years have had no issues, it will be interesting to see the finished item of anyone who has made / makes upright side panels to fit around there pond....... unless you make a near complete solid structure right the way around your pond your going to get wind chill which leads to diminishing temps quite quickly, if your worried about gas release and oxygen then raise the panels from the pond surface area using some decent wood supports for the poly to sit on, the gap between my pond surface and polycarb is around 7inches, as there are 3 panels i always have one at the far end just very slightly open for gas release purposes, some of us have been discussing using tarp or heavy duty polythene sheeting like they use in the fields for poly tunnels but will it rip in a storm or put pressure on your pergola structure as it will act like a kite...... this summer i purchased some very thick plastic bags to put my solar heater inside up on my pergola roof with a view to help trap hot air, within 3 months and in our summer climate what winds we have had totally destroyed the plastic bag, ripped to shreds......
    2200 gallons,infinity window,
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