RAISED POND PART IV - TOP COLLAR

Right then.  So far we have a large timber box filled with plastic and water that hasn’t leaked in three days.  Great but it doesn’t really look very pretty, does it?

 

No leaks but very unsightly

There’s that unsightly layer of overhang that needs sorting out.  A bit like my muffin tops only it’ll be a lot easier to trim these off.  Mine are going to need liposuction! 

But before we take scissors to the offending surplus underlay and lining, we’re going to add a nice timber collar to finish off the top edge of the pond and hide everything else.  

To make the top collar, use some more pieces of reversible decking.  This time cut the planks slightly longer than each side to allow for the corners to be mitred.  If you really can’t be bothered with all that mitre nonsense then just use straight pieces as it really doesn’t matter.  We used 2 x 2.4 m lengths of decking to cut out 2 x 1.19 cm long sections and 2 x shorter sections each 0.94 cm long.

 

Top collar pieces

Again, waterproof your timber with a suitable weatherproof product and leave to dry before fitting.

 

Suitably weatherproofed

The top collar is rather like making a picture frame that is going to sit along the top edge of the pond structure.  Each section of the frame needs to be centrally balanced on the edge so that it slightly overhangs both the inside and outside of the pond.

 

Top collar should overhang at the front and back

Right, now you can get the scissors.  Carefully trim off any excess liner/underlay so it is close to the top edge where it can’t be seen once the collar is fitted. 

Time to get rid of the excess overhang

Trim carefully with scissors close to the edge

Much neater and with enough overhang to trap under the collar

Screw each collar section into position carefully, tightly abutting the mitred corner joins – remember whatever you do, don’t pierce the liner below the waterline!  It’s quite a feat fitting the collar as unless you’ve made your pond with sleepers there is only a narrow edge for you to screw into.

 

Align the mitred corners before screwing down

And now for the great pond unveiling – ta dah!  All it needs is a few plants plus a solar fountain to create a calming oasis and habitat for any passing frogs or local wildlife.

Now top up with water to the desired waterline

Finished pond ready for plants and solar fountain

I declare our 'Special Landscaping Operation' to be a resounding victory - Russia take note!

View along the back border

View across from pond to RNLI shed

Border planting completed

RAISED POND PART III - LINING

If you thought laying underlay in a pond was a big faff then wait until you have to fit the pond liner.  Believe me, I don’t ever want to have to do that again! 

Great care needs to be taken when fitting a pond liner.  You want to make sure you don’t snag or puncture it in the process or else it will be useless and money wasted hence why I'm fitting this in situ to prevent rips from moving.  

When making up the corners, try to get as few creases as possible and ensure the corner folds are above the waterline or the pond may leak. This is easier said than done as pond liners are made of thicker, less flexible material than underlay so a lot harder to work with. 

Again, I started this process by laying out the entire liner on a flat surface and folding into thirds to create my pond liner ‘sandwich’ in order to get the thing into the pond. 

Carefully fold the liner over the top edge of your pond box but before securing it down, push the liner well into the bottom, around any plant shelves and into the corners so it won’t pull when you fill with water.  The last thing you want after all this effort is for it to tear with the weight of the liquid.  Use the clamps from the underlay layer to help you keep the liner in place as you work your way round the edges. 

Liner clamped into position

When you are satisfied that everything looks flat, folded and is not pulling then secure into position at the top edge.  I used a staple gun for this but remember not to staple below the natural waterline or you’ll get leaks from the staple holes.  I found it best to partially fill the pond then adjusted the liner with the weight of the water before finally stapling it down.

 

Partially filling with clamps in place 

And now, the moment of truth.  It’s time to fill that pond with water.  Do this slowly and keep checking for any leaks or fabric that looks like it’s being over-stretched.  Woo hoo – there are no leaks!!

Unlike the Titanic - no leaks

RAISED POND PART II - UNDERLAY

Okay so far?  Good, we’ll move on to the next part of the project and this is where it all starts to get a bit trickier.

Waterproofing your raised pond

As the raised pond is made of timber then to help it weather the elements and extend the life of the structure it’s a good idea to give it a coat of something waterproof such as Cuprinol or other outdoor paint/varnish. Apply as per the instructions on the tin then leave to dry thoroughly. 

 

Looks better now it's painted

Once assembled and painted, position your pond structure in what will be its final resting place as the underlay and liner will be fitted in situ.  It’s going to be a tight space to work in – note to self; eat less cookies!

 

Putting the pond into its final position

Not much space to work in

To create shelves for pond plants, I’ve placed a few leftover bricks on a layer of sand sprinkled on top of the concrete base.  These are mostly at the back corners to raise any plants off the bottom.

 

Create submerged shelves for plants using bricks

When you have finished preparing the inside of your pond structure, it’s time to think about lining the inside with special pond liner and underlay.  I say ‘think’ because you really do need to work out how to do this carefully before getting stuck in. 

Pond liner and underlay can be easily purchased online from many suppliers.  I’m not going to give a lengthy explanation as to all the different types of pond liner/underlay available or recommend a specific type as there are loads to choose from.  This is for you to research online and purchase according to your preference or budget but I ended up getting mine from www.pondkeeper.co.uk who provided free underlay with the purchase of pond liner.  Most websites have a pond liner calculator so that you can work out how much you need based on the dimensions of your pond.

 

Just one of many online suppliers

There are lots of different types of liner or underlay

The underlay is a protective layer to ensure the pond liner is not punctured by any sharp edges.  The basic underlay I bought was similar to a fabric type of weed membrane, soft and easy to fold into place.  Begin by laying out all of the underlay on a flat surface so you can see the whole size/shape of it beforehand. 

 

I was able to get a double layer of this in the pond it was so big

I found it easier to place the whole piece of underlay in the pond by folding the fabric into thirds first with one section on top of the other.  This underlay sandwich can then be carefully placed into the pond structure and unfolded one layer at a time. 

Make sure the underlay lays flat on the bottom of the pond without being stretched so that it doesn’t tear when you place the liner on top and fill with water.  There should be as few creases as possible although with such a large piece of underlay I found it quite hard not to fold it a million times especially in the corners where you need it to sit quite flat.

 

Underlay carefully laid in position

With the underlay carefully laid in your pond, gently clamp to hold it in position whilst you go off for a well-earned cup of tea.  Don’t worry about the overlapping fabric at the top edge as there’ll be plenty of time to trim that later.

BUILDING A RAISED POND - PART I

Building a raised pond is perhaps not quite as daunting a project as it first sounds as in simplistic terms you are essentially making a box lined with waterproofed plastic or rubber. 

In the next couple of blog posts, I’m going to run through how we built a raised pond for the back corner of the garden. 

As with any good project, preparation is key and its always worth spending a good chunk of time on planning, scribbling out your ideas with a hot cuppa and a cookie until you are clear what it is you want to achieve and how you are going to get there.  When you’ve nailed this bit then it’s time to pull on the wellies and get stuck in.

 

Top quality design sketch

Once you’ve decided where your pond is to be sited, measure up the space then prepare a design sketch of what you would like your finished pond to look like.  Include measurements.  My best sketched plans always look like they fell out of a packet of cornflakes but you really don’t have to be a professional garden designer for this project, it’s that simple.  

Our raised pond will sit on a large rectangular bit of concrete that may once have been the base of a greenhouse so I’ve made the overall pond dimensions slightly smaller than the concrete base to allow an overhang.

 

Using an old concrete base on which to put the pond

Using your measurements, work out how much timber you will need.  We’ve used reversible decking planks for the main body of the pond with 4 square pieces of timber for the internal corners. The pond will be 3 planks high.  To make a pond like ours, you’ll need 6 x 1.10 m long pieces for front and back plus 6 x 0.80 cm pieces for the sides.  Don’t forget the 4 corner bits!

 

Front, sides and internal corner pieces

I purchased the decking timber at Covers Timber and Builders Merchants in Chichester who cut this exactly to our measurements.  I’ve found Covers to be far more accommodating than B&Q at cutting timber.  B&Q may have fancy wood cutting machines but the staff appear to be reluctant to cut anything and always end up citing ‘health & safety’ for not cutting anything smaller than a whole sheet of MDF.  Covers, on the other hand, will cut pretty much anything wooden to any size which is far easier than struggling to do it yourself at home. 

Now you have all the timber cut to size, it’s time to begin assembly.  To make each side, begin by attaching the shorter side decking planks to the corner battens, securing these in place with wood screws.  Layer up tightly to avoid unsightly gaps and make sure the screws do not come through the corners or you may pierce your pond liner.

 

Join short planks to the internal corner battens to create side walls

When both of the short sides have been put together, join the longer sections at the corner.  This is a 2-person job as one will need to hold the plank keeping everything aligned whilst the other person screws it into place.  

 

Join the longer planks to each of the short sides at the corner

We found it easiest to screw both bottom planks in place first to give our box stability and make it easier to add the other layers.  Work your way up from bottom layer to top.

Create your box by adding both bottom planks first then layer up

You may notice that we have not added a bottom or feet to our box.  As we are using the concrete pad as our bottom then we didn’t think it necessary but there’s no reason why you can’t add these to your design.

 

Continue adding planks until you have a bottomless box

With pond base assembled, its then time to order some pond liner and underlay as you’ll need these for the next phase of the project.