Building a Raised Pond: Brick, Block, Pre-Formed & Timber Methods

Constructing a Raised Garden Pond

Block or Brick Structure

After concrete foundation sets, build walls trapping polythene membrane between inner/outer skins. Use running bond (half overlap), build corners first with spirit level and set square. Keep faces vertical, courses horizontal, joints uniform (~1 cm / 3/8 in). Use gauge rod (marked batten) for course height. Render inner faces, add coping. Apply waterproof sealant to prevent free-lime leaching.

Using a Pre-Formed Pond

Build concrete strip foundations (20 cm / 8 in wider than walls, 10 cm / 4 in deep). Place pond, mark outline, build walls allowing backfill space (use sand/pea gravel). Finish edge and cap. Disadvantage: broad top edge. For small ponds, secure pond first, then build walls tightly around it for a simple brick overhang.

Lined Raised Ponds

Same as rendered block/brick but omit render/membrane. Near completion, install liner, trap edge under coping or final brick row. Protect liner from abrasion with fleece/geotextile on brickwork (industrial adhesive).

Timber alternative: level base slightly larger than pond. Treated timber (min 10×15 cm / 4×6 in) — old railway sleepers work. Cut to size, notch ends for halving joints, check right angles, fasten with dowels/rustproof screws. Keep each length level. Line interior with fleece, lay pond liner (rubber best, PVC/LDPE acceptable), fold corners substantially. Secure liner under top timbers or with narrow laths above water level.

Step-by-Step: Building a Raised Brickwork Pond with Liner

1. Mark area, excavate foundation 10 cm deep, 10 cm larger than external pond dimensions.
2. Add crushed hardcore, then level concrete layer (same mix as in-ground pond).
3. Build walls from corner using English bond; check level/plumb regularly.
4. Secure fleece/geotextile/polystyrene to brickwork with industrial adhesive.
5. Install liner (welded rubber best), fit neatly to corners, turn over top edge.
6. Finish with coping stones or final brick row on mortar, trapping liner just above water level.