Fitting Your Pond Liner and Underlay

Underlay

Always use a good aquatic underlay, like Permalay or Polyfibrelay, to protect your liner. People often use other materials to underlay their pond like old carpet or even newspaper but these are likely to rot and then the stones that they were covering will poke through. If this happens a couple of years down the line when the plants and fish are established and the pond is starting to look great you’ll have to take out the whole liner and replace it; not a nice job!

Fitting the pond liner

When you are ready to fit your pond liner it is a good idea to spread it out on the lawn first. Avoid concrete or tarmac as you may damage the pond liner, especially if you walk on it.

Choose a fine day and (if you can!) a sunny one. Allowing the liner to warm up will greatly increase its flexibility for the next stage.

Get help with putting the liner into the pond, the bigger the liner the more people you’ll need. A smallish liner can be easily handled by two people but they can get heavy as they get bigger. A good rule of thumb is that most liners weigh around a kilo per square metre i.e. 10 x 10m = 100 Kg (or you could use 2lbs a square yard and not be far wrong).

Having got the liner roughly in the hole the best way to form it to the shape of the pond is to get in, without your shoes and socks. The amount of folding you’ll have to do will depend on how complex the shape of your pond is.

With a rectangular pond it is a bit like wrapping a book as a present, you’ll end up with a triangular fold at each corner that you need to tuck in. You can fold the top of this over onto the outside of the pond and it will be held in place by your edging slabs (or whatever else you have chosen). You might want to seal this down with tape to make the job look a little neater and to stop anything getting caught in the fold. Bradshaws’ Polyfix custom kits contain all the tape you’ll need.

If your pond is an irregular shape then you’ll have to make a series of folds or overlaps to get it to the right shape. This can take a while and it’s usually easier if you start to fill the pond as you are doing this. Take care not to stretch the liner into shape though and don’t be tempted to start the edging process until the final position of the liner is reached.

If you have access to one then it can be a good idea to use a water meter when filling up the pond at this stage. These usually fit onto the tap and then the hose fits onto the meter. This will tell you exactly how much water is in your pond. With a rectangular pond it is less important as you can always work out the volume later. You can sometimes hire a water meter from your local pond shop.

Click here to buy pond liners from Bradshaws Direct
Click here to buy pond underlay from Bradshaws Direct

Now that you know how to lay your pond liner, why not take a look at one of our other guides:
Finishing off the pond edge
Planting
Pond Filters
Connecting the Pond Pump and Pond Filter
Fountains
Waterfalls

Or click here to see the full list of guides