Balcony Waterproofing and Podium Waterproofing: Under Tiles and Under Traffic

Balcony leakage: check where the water goes first

A damp ceiling in the flat below, a stain on the underside of the balcony, water creeping under the door into the room, white salt lines at the tile joints: these are the signs of balcony leakage. A balcony or podium is a small roof that people walk on, and its waterproofing is buried under tiles, paving or soil. That is why the membrane has to be right, and proven watertight, before anything covers it. Six checks tell you what kind of repair the balcony needs.

Find the right balcony waterproofing method

Match what you found to one route. Each tells you what is done and takes you to its section. Balconies, podium slabs, car park decks and planters share one rule: the membrane is tested with water before it is covered.

Repair first, break last. Where the tiles are firm, the joints and edges are treated and the floor is left alone. The floor is opened only when the layer under the tiles has failed or the slope is wrong.

Balcony and podium membrane finder

Armstrong makes membranes that go under tiles and soil, and systems that stay exposed under traffic. Every one is a sound choice. Answer three questions for a starting point, then confirm it with an Armstrong expert.

Pipe and floor-joint bore packing

Water seeps into a slab around pipes and along floor joints, where the original concrete never bonded to the pipe or the next pour. Packing the bore closes that path. Doses, thicknesses and coats are the standard figures; the site and the exposure decide where they move.

1. 1
   Open a groove

   Chip a groove 6 to 10 mm wide around each pipe or along each floor joint, and clean out dust and dirt.Why: The compound needs a clean, defined groove to lock into. A hairline gap cannot hold it.
2. 2
   Pack it

   Seal the groove with the instant plugging compound WONDERSEAL PLUG XL, finishing level with the surface all round the pipe.Why: It sets fast, so it stops water that is still moving and does not shrink out of the groove.
3. 3
   Seal trap and pipe joints

   Seal the joints of traps and pipes with an acrylic putty of ROOFCOAT FLEXI 100, cement and sand.Why: This flexible putty absorbs the small movement of the pipe, which a rigid mortar does not.

Seeping concrete: grout through drilled holes before any lining goes on

When water leaks, seeps or sweats through porous, honeycombed or cracked concrete, it has to be stopped inside the concrete first. This is the standard negative-side method for tanks, pools, basements, lift pits and retaining walls. A lining laid over concrete that is still seeping is pushed off by the water behind it: it blisters, lifts and fails. Grouting through drilled holes fills the internal voids and capillaries along the path of the water, so the surface is dry and sound before the coating or membrane goes on. Doses, thicknesses and coats are the standard figures; the site and the exposure decide where they move.

1. 1
   Drill the injection points

   Drill 12 to 14 mm holes with an electric drill into the leaking or honeycombed zone, to the depth the member needs (14 to 16 mm on thick retaining walls).Why: The holes intercept the pathways the water is travelling along, so the grout reaches the voids instead of just sitting on the surface.
2. 2
   Fix the nozzles

   Fix a rubber injection nozzle in each hole with a quick-setting putty of cement mixed with the set accelerator RAPIDSTRONG QS 113. For active flow, the single-component plugging compound RAPIDSTRONG PLUG can be used to fix the nozzle instead.Why: The nozzle must be locked into the hole before pumping starts. If it is not, the pressure blows it out and the grout runs back out of the hole.On site: The datasheet gives RAPIDSTRONG QS 113 at 500 ml to 2 L per 50 kg of cement and asks for a site trial, so trial the dose on the job before fixing every nozzle.
3. 3
   Seeping or sweating concrete: cement slurry

   Mix a cement slurry with a non-shrink grout additive and pump it into each nozzle with a grout pump at about 140 psi, until that point refuses to take any more. Any of three additives can be used: RAPIDSTRONG GROUT ADMIX at 250 g per 50 kg of cement, RAPIDSTRONG GROUT PB 66 (a polymer grout additive, dosed as on its datasheet) or ROOFEX GP (a crystalline grout compound, dosed at 250 g per 50 kg of cement).Why: The slurry fills the internal voids and capillaries. The additive keeps it from shrinking away from the concrete as it sets, which an ordinary cement slurry does, and the crystalline option also seals the capillaries.On site: Work from the lowest nozzle upward on a wall, so the slurry pushes the water and air out ahead of it.
4. 4
   Running or gushing water: polyurethane resin

   Where water is flowing or gushing, cement slurry would simply wash away before it sets. First stop the surface flow with RAPIDSTRONG PLUG in a V-groove, then inject RAPIDSTRONG GROUT PU, the single-component polyurethane grout, with air-compressed injection equipment at about 500 g per grout point.Why: The polyurethane reacts with the water itself, expanding and stiffening to block the flow, so it works where cement cannot.On site: A hard-working point can take 0.3 to 0.75 kg. Polyurethane grouting alone only stops the flow; it is not a guaranteed waterproofing system, so follow it with the lining or coating the structure needs.
5. 5
   Remove the nozzles and seal

   Once grouting is complete, remove the nozzles and patch every hole flush with a putty of ROOFCRETE AR and cement.Why: This leaves a smooth, sound, watertight surface ready for the final lining.
6. 6
   Check before lining

   Look at the face again after the grout has set. Any point still wet gets another nozzle beside it before the coating, membrane or plaster goes on.Why: A single wet patch left behind becomes the first blister under the new lining.

Balcony waterproofing: the standard sequence, step by step

This is the standard sequence for this area, in the order it is carried out. Each step prepares the surface for the next, so a step skipped or done out of order shows up later as a leak, a blister or a hollow tile. Doses, thicknesses and coats are the standard figures; the site and the exposure decide where they move.

1. 1
   Prepare the surface

   Clean the surface of dirt, dust and old coatings. Chip off loose mortar and cement lumps with an electric chipping machine, remove the debris and wire-brush the surface.Why: Every membrane in this sequence is only as good as its grip. It bonds to clean, sound material, not to dust or loose screed.
2. 2
   Groove and seal cracks and joints

   Open every crack and joint to a V-groove about 6 mm wide and deep, clean it out, and fill it with ROOFEXSEAL PU 212, the single-component polyurethane sealant.Why: A hairline crack moves with temperature. A rigid coating over it cracks along the same line, but a flexible sealant in the groove moves with it.
3. 3
   Stop the leaks

   Where water comes through, grout it through drilled holes as in the section above: 12 to 14 mm holes, rubber nozzles fixed with cement and RAPIDSTRONG QS 113, cement slurry made with RAPIDSTRONG GROUT ADMIX (250 g per 50 kg of cement), RAPIDSTRONG GROUT PB 66 or ROOFEX GP pumped at about 140 psi until refusal, then seal the holes with ROOFCRETE AR and cement.Why: The membrane goes on a dry, stable surface. Water pushing from behind lifts any coating laid over it.
4. 4
   Two coats of the cementitious membrane

   Apply two coats of ROOFBOND RFX PLUS 210 as a slurry, about 1.5 kg per sq.m in total, over the slab and up the vertical surfaces to 300 mm above finished floor level. Put the second coat on once the first has set enough to take it.Why: Two coats close the pinholes a single coat leaves, and the 300 mm upturn means water on the floor cannot run behind the membrane at the wall.
5. 5
   Pond to test

   Pond water on the floor for 7 days and check the ceiling below for any damp patch before anything is laid over the membrane. Some specifications call for a ponding test without fixing a period, so the test period is set by the job.Why: This is the only moment a leak can be fixed easily. Once the screed and tiles are on, finding and repairing the same leak means breaking all of it out.
6. 6
   Protective plaster over the membrane

   Lay a protective plaster about 20 mm thick on the floor and on the walls up to 300 mm, in 1:3 cement mortar mixed with CONPROOF 500 at 500 ml per 50 kg bag. Form a cove at the floor-wall junction, finish with a broom texture to take the next layer, and cure for 7 days.Why: Tiles and screed bond to a plaster, not to a membrane. The plaster also stops the membrane being scraped when tiles are laid.On site: Tiles go on this plaster or screed, not directly on the membrane.
7. 7
   Form the cove at the wall junction

   Chip off loose material and clean the junction. Apply ROOFBOND SBR 401 mixed with cement as a bond coat, then form a cove at the 90 degree junction up to 6 inches (150 mm) in 1:4 cement-sand mortar mixed with CONPROOF LW 200 at 200 ml per 50 kg of cement, finished neatly.Why: A sharp 90 degree corner is where coatings tear and crack first. A cove lets the membrane run round the corner as one continuous skin.
8. 8
   Seal around every pipe

   Seal the periphery of each pipe with polymer concrete made with ROOFCRETE AR 576. Fix a socket around the pipe, grout the socket with the same polymer concrete, and prove it with a ponding test.Why: A pipe passing through a slab leaves a gap that ordinary mortar shrinks away from. This is one of the commonest places for a leak to come back.

Balcony waterproofing under tiles, step by step

Routes A and C: a new balcony, or one stripped back to the slab. The membrane goes on the slab, is turned up the walls and the door threshold, is flood tested, and only then covered. Four Armstrong membranes suit this job: ROOFCOAT FLEXI 100, ROOFBOND RFX PLUS 210, ROOFCOAT PU 2K and ROOFEX 2K 711. Any of them can be used under tiles. Pick the one that fits the site, or ask an Armstrong expert. RAINPROOF PU 400 is an exposed membrane and is not used under tiles.

1. 1
   Strip to a sound surface

   On an old balcony remove tiles, bed and loose screed down to the slab. On a new one remove dust, laitance and curing residue. All loose, old and flaking material comes off before any treatment.Why: The membrane bonds to sound concrete, and loose screed or tile bed under it gives way and takes the membrane with it.
2. 2
   Repair the slab

   Open cracks to a 4 to 5 mm V-groove and seal them with ROOFEXSEAL PU 212. Rebuild broken or honeycombed patches with repair mortar gauged with ROOFCRETE AR 576 at 2 to 5 litres per 50 kg bag of cement, placed over a bond coat of ROOFBOND SBR 401 mixed 1:1 with cement while that coat is still tacky. Where steel is exposed and rusted, it is cleaned and given one full coat of ALSTRONG ZP 777 and the repair follows the structural concrete repair page.Why: Cracks and broken edges are repaired first, since the membrane cannot bridge a gap that moves.
3. 3
   Grout pipes, posts and the outlet

   Pack around every pipe, railing post and outlet with a non-shrink grout made with RAPIDSTRONG GROUT ADMIX, at 250 g per 50 kg of cement, and use the grout within 30 minutes of mixing. Armstrong also gives a polymer putty of ROOFBOND SBR 401, cement and graded sand at 1:1:1 for sealing pipe penetrations flush. Fix the outlet at the low point.Why: Every pipe, post and outlet leaves a gap through the slab, and non-shrink grout closes it so water cannot follow them down.
4. 4
   Form the coving

   Build a rounded fillet where the floor meets the walls, in mortar gauged with ROOFBOND SBR 401 and CONPROOF LW 200, so the membrane turns the corner in a curve and not at a sharp angle. The usual practice is a 1:4 cement-sand cove up to 6 inches (150 mm) over a ROOFBOND SBR 401 bond coat, mixed with CONPROOF LW 200 at 200 ml per 50 kg of cement.Why: A rounded fillet lets the membrane turn the corner as one skin, where a sharp corner tears it.
5. 5
   Give the floor a slope

   Water must run to the outlet on its own and away from the door. Correct the slope in the slab or the screed, never by thickening the membrane.Why: Water that cannot run off stands and finds the weak point, so the floor falls to the outlet and away from the door.
6. 6
   Apply the membrane in two coats

   ROOFCOAT FLEXI 100 is mixed 1 litre to 2 kg of regular cement and 200 ml of water and applied in two coats, the second at right angles to the first, 3 to 4 hours later. ROOFBOND RFX PLUS 210 is mixed from the 5.1 kg of liquid and 15 kg of powder in its 20.1 kg unit and applied in two coats, 3 to 4 hours apart. ROOFCOAT PU 2K is mixed 1:2 by weight, applied on a pre-wetted surface in two crosswise coats, 3 to 4 hours apart. ROOFEX 2K 711 goes on a dampened surface. Carry every coat over the coving, up the walls and up the door threshold. ROOFCOAT FLEXI 100 and ROOFBOND RFX PLUS 210 can both be applied with fibre mesh, and the mesh is always layer 2, bedded after the first coat.Why: Two coats close the pinholes in the first, and the mix ratio gives the stated flexibility and strength.
7. 7
   Cure

   ROOFCOAT FLEXI 100 is cured for 7 days after its second coat. ROOFBOND RFX PLUS 210 is water cured for 7 days before flood testing. ROOFCOAT PU 2K is air cured for 3 to 5 days before tiling. ROOFEX 2K 711 is mist cured 3 to 4 times a day for 2 to 3 days and needs 48 hours before foot traffic.Why: A membrane that is covered or wetted before it cures is damaged, so it is allowed the stated time.
8. 8
   Flood test before anything covers it

   Block the outlet, flood the floor to a shallow depth and hold it for 24 to 48 hours. Check the ceiling below and the room inside. A leak found now is a brush repair. A leak found after tiling is a broken floor. Some specifications hold the water for 7 days.Why: A flood test shows any leak while it can be fixed easily, before the screed and tiles hide it.
9. 9
   Lay the protective screed

   Lay the screed to slope over the membrane, with CONPROOF LW 200 at 200 ml per 50 kg bag of cement. Orders place a protective screed or plaster over the membrane before tiling.Why: The screed protects the membrane from tile work and traffic, and gives the slope.
10. 10
    Fix the tiles

    Use a polymer tile adhesive, not plain cement mortar. TILEX 353 is a deformable C2TES1 adhesive for exterior floors, TILEX 351 PLUS is a C2TE adhesive for external tiling, and TILEX 521 is a two-component S2 adhesive listed for balcony tiles. TILEX 512 is a PU hybrid adhesive for large format tiles and stone. Pick the one that fits the tile and the site.Why: A polymer adhesive stays bonded as the balcony expands and shrinks, where plain mortar lets go.
11. 11
    Grout and seal the perimeter

    Grout with TILEX EPOXY STAIN FREE 100, which is non-absorbent, or TILEX TG S 1500 for wider outdoor joints. Leave the joint between the floor tiles and the wall open and fill it with ROOFEXSEAL PU 212, not grout. It needs no primer on dry concrete, tile and stone, does not stain natural stone, and is tack-free in 50 minutes. Movement joints in larger areas take ROOFEX-SEAL PS, with the joint twice as wide as it is deep.Why: Non-absorbent grout stops water entering the joints, and a flexible seal at the edge takes the movement.

Balcony leakage solution without removing tiles

Route B. Tiles themselves do not let water through. The joints, the edges and the points where something passes through the floor do. Where the tiles are firmly bonded and the balcony drains, the leak can often be treated from the surface.

1. 1
   Confirm the tiles are bonded

   Tap every tile. This method is for tiles that ring solid. A few hollow tiles can be lifted and refixed; many hollow tiles mean Route C.Why: This method keeps the tiles, so they have to be sound, and hollow tiles mean they are not.
2. 2
   Rake out the joints

   Remove loose, cracked and powdery grout from every joint, clean out the dust and let the joints dry.Why: New grout bonds to clean, firm joint sides, and old powdery grout does not.
3. 3
   Regrout

   Fill the joints with TILEX EPOXY STAIN FREE 100, a non-absorbent epoxy grout, or with TILEX TG S 1500 where the joints are wide.Why: Non-absorbent grout stops water entering through the joints, which is how most tiled balconies leak.
4. 4
   Seal the perimeter and the threshold

   Rake out the joint between the floor tiles and the wall, and the joint at the door frame and threshold, and fill them with ROOFEXSEAL PU 212.Why: The edge and the threshold move more than the field of tiles, so a flexible sealant goes there.
5. 5
   Seal around posts, pipes and the outlet

   Clean around each railing post, pipe and the outlet and seal with ROOFEXSEAL PU 212. Where the grout around a pipe has failed, repack it with non-shrink grout made with RAPIDSTRONG GROUT ADMIX.Why: Posts, pipes and outlets pass through the floor, and water follows them down.
6. 6
   Refix the few hollow tiles

   Lift them, remove the loose bed, repair with ROOFCRETE AR 576 over ROOFBOND SBR 401, coat the opened patch with ROOFCOAT FLEXI 100 or ROOFBOND RFX PLUS 210 in two coats and refix the tiles with a TILEX adhesive.Why: Hollow tiles let water in under them, so they are lifted and refixed in a full bed.
7. 7
   Coat with a transparent coating

   On a completely dry surface, coat the whole floor and the skirting with RAINSEAL CLEAR 202 or RAINCARE PU CLEAR. Both keep the look of the tiles. RAINSEAL CLEAR 202 goes on in two coats, and 1 litre covers 30 sq.ft in two coats.Why: The clear coating forms a film over the whole floor without changing its look.
8. 8
   Flood test

   Let it cure, then block the outlet and flood the floor for 24 to 48 hours. RAINCARE PU CLEAR takes a minimum of 72 hours to cure fully.Why: A flood test proves the repair, and the coating is cured first so it is not damaged.

New tiles over old tiles

Where the old tiles are bonded but worn, TILEX 521 is a two-component adhesive made for fixing new tiles over existing ones, and is listed for balcony tiles. Tiling over old tiles does not waterproof the balcony by itself. Treat the joints and edges first. The tile fixing and grouting page covers adhesive and grout selection.

Podium waterproofing and car park deck leakage: exposed, trafficable systems

Routes D and E. A podium slab, a walkway or a parking deck is a large flat roof with people, vehicles or landscaping on it and occupied space below. Some are finished with paving on a screed, and take a membrane under it exactly as a balcony does. Others are left as a coated surface, and then the membrane itself has to take the wear and the sun.

Sequence for an exposed deck

1. 1
   Clean and inspect

   Grind and wire brush the deck, then clean it with compressed air and a high-pressure water jet. Remove all loose, old and flaking coating, oil and laitance. Mark cracks, joints, hollow patches and low spots.Why: The system bonds to a clean deck, and inspection finds the cracks and hollows before they are coated over.
2. 2
   Repair

   Seal cracks with ROOFEXSEAL PU 212 in a V-groove. Patch hollow and debonded areas with a bonding slurry of ROOFBOND SBR 401 and screed mortar, and rebuild broken patches with ROOFCRETE AR 576 mortar over the same bond coat. Correct low spots so water reaches the outlets.Why: Cracks and debonded areas are repaired first, since a membrane over them is unsupported.
3. 3
   Detail the joints

   Expansion joints are built to move. They take ROOFEX-SEAL PS over its primer and are never buried under a rigid layer. It comes in a gun grade for vertical joints and a pour grade for joints in the deck, takes joints 6 to 25 mm wide in one pass, and is sized with the width twice the depth. RAINSEAL BS is an elastomeric bitumen compound for joints in parking places and platforms. The expansion joint sealing page covers joint design.Why: Expansion joints move, so they take a flexible sealant and are not coated over.
4. 4
   Form the coving and treat the upstands

   Form a coving at walls, kerbs and planter sides and carry the system up them.Why: Walls, kerbs and planters meet the deck at corners, and the system is carried up them so water cannot get behind it.
5. 5
   Apply the first layer

   In the Armstrong five-layer systems the first layer is the first coat of the system. In RAINCARE PRC it is a black base primer. RAINPROOF PWR 690 is different: it requires a primer of SHINESHIELD WP 305 at a minimum of 0.15 mm.Why: The first layer is the base of the five-layer system, and the later layers build on it.
6. 6
   Lay the fibre mesh as layer 2, then three coats

   Fibre mesh or geo-fabric is laid as the second layer. The third, fourth and fifth layers are coats applied over it, each 3 to 4 hours after the one before. That makes four coats and one layer of mesh.Why: The mesh reinforces the film over cracks, and the coats over it build the thickness.
7. 7
   Polyurea option

   RAINPROOF PWR 690 is mixed Part 1 to Part 2 at 2:1 and applied at 1.2 to 2.0 mm thickness, about 1.2 kg per sq.m at 1.2 mm. RAINPROOF PHB 660 is sprayed with heated plural-component equipment in two coats by trained applicators. Both are two-component, solvent-free hybrid polyurea and polyurethane coatings.Why: Polyurea gives a fast-curing, tough membrane for decks that take heavier traffic.
8. 8
   Cure and flood test

   Let the system cure fully, then flood test bay by bay before the deck is opened.Why: Testing bay by bay finds a leak while it is local and easy to fix.

Floor coatings for the inside of a covered car park, as distinct from waterproofing a deck open to rain, are on the epoxy flooring page.

Planter box leakage and terrace garden waterproofing

Route F. A planter is a small tank that is never emptied. The soil stays wet, the water carries fertiliser salts, and nobody can see the membrane again once the soil is in. The waterproofing therefore sits on the inside faces, the side the water touches, and is protected before the soil goes in.

1. 1
   Empty and clean

   Remove soil, roots and old lining. Take off all loose, old and flaking material down to sound concrete or plaster. Let the surface dry enough to inspect.Why: The lining bonds to sound, clean concrete, and roots and old lining are in the way.
2. 2
   Repair cracks and corners

   Open cracks to a 4 to 5 mm V-groove and seal them with ROOFEXSEAL PU 212. Rebuild broken patches with ROOFCRETE AR 576 over ROOFBOND SBR 401. Form a coving at every internal corner.Why: A planter holds water against the slab at all times, so every crack is a leak path.
3. 3
   Fix and grout the drain outlet

   Every planter needs an outlet at its low point. Grout around the outlet pipe with non-shrink grout made with RAPIDSTRONG GROUT ADMIX. A planter without a drain holds water against the membrane all year.Why: Water must have a way out at the low point, and the grout stops it going down the pipe.
4. 4
   Apply the membrane on the base and all sides

   Two coats of ROOFCOAT FLEXI 100 or ROOFBOND RFX PLUS 210, carried up the full height of the inside faces and over the top edge. Both are flexible cementitious coatings that stay sound under constant damp, and both are abrasion resistant. Armstrong lists ROOFCOAT FLEXI 100 for roof gardening and garden slabs. On a weak or cracked planter, use the reinforced build-up: a first coat, 45 GSM fibre mesh as layer 2, then three further coats.Why: The membrane is carried up all sides, since water stands against the walls as well as the base.
5. 5
   Flood test

   Block the outlet, fill the planter with water and hold it for 24 to 48 hours. Check the slab below and the outside faces.Why: The planter is filled with water, since that is the load it carries, and checked for any leak below.
6. 6
   Protect the membrane

   Lay a protective screed on the base, with CONPROOF LW 200 in the mix, so that tools and roots do not reach the membrane. On the sides, use a mortar screed or protection board, as Armstrong specifies before backfilling against a waterproofed retaining wall. On soil-facing faces, that Armstrong procedure also puts two protective coats of RAINSEAL BMW 250, diluted 20% with water, over the cementitious membrane before the screed or board. RAINSEAL BMW 250 is listed for terrace roof gardening, and 1 litre covers 30 sq.ft in two coats.Why: Roots, soil and tools damage a membrane, so a screed covers it.
7. 7
   Drainage layer, then soil

   Place a drainage layer and filter fabric over the screed, keep the outlet clear, then fill with soil.Why: The drainage layer lets water reach the outlet, and the filter fabric keeps soil out of it.

Named systems listed for planters: RAINPROOF PHC 5 Layer System for planter boxes, with crack bridging up to 3 mm, and RAINSEAL HFC 5 Layer System and RAINCARE PRC 5 Layer System for planter areas. A garden laid over a whole terrace is covered on the terrace waterproofing page, which uses the same two membranes under a protective layer.

Best waterproofing for a balcony: Armstrong membranes and systems compared

There is no single best waterproofing for a balcony or podium. The first question is whether the membrane will be covered or left exposed. The tables give every Armstrong product that suits each case, with its stated figures. None is a lesser product.

Membranes that go under tiles, paving, screed or soil

Systems and membranes left exposed to weather and traffic

Each five-layer system has four coats and a fibre mesh or geo-fabric as its second layer, and comes in packs of 5 and 20 litres. The second layer is stated as fibre mesh or geo-fabric for all of them.

Balcony waterproofing chemicals and products by stage of work

How much waterproofing material for a 60 sq.ft balcony

A balcony 12 ft by 5 ft has 60 sq.ft of floor. With the membrane turned up about 1 ft on 22 ft of wall and threshold, the coated area is about 82 sq.ft (7.6 sq.m). Quantities below are from each product’s stated coverage. The upturn height is an example. An Armstrong expert confirms the final quantity after seeing the site.

Standards and tests for balcony and podium waterproofing

• The flood test: the finished membrane is ponded and the space below checked before any screed, tile, paving or soil covers it.
• IS 3067 is the Indian code of practice for damp-proofing and waterproofing of buildings. It gives a 75 mm radius fillet at junctions and takes the treatment at least 150 mm up the wall on roofs.
• ROOFCOAT PU 2K complies with EN 1062-3 and EN 1504-2, with nil chloride permeability to ASTM C 1202.
• ROOFCOAT FLEXI 100 is tested to ASTM D412, ASTM C836 and ASTM D4541.
• ROOFBOND RFX PLUS 210 is tested to ASTM C836, ASTM D4541 and EN 1062-7.
• The Armstrong five-layer systems are listed to ASTM G154, ASTM C836 and ASTM C297.
• TILEX 353 complies with IS 15477:2019 and EN 12004 class C2TES1. TILEX 521 complies with EN 12004 class D2TES2.
• ROOFEX-SEAL PS complies with BS 4254 and ASTM C 920. ROOFEXSEAL PU 212 complies with IS 11433:1985.
• CONPROOF LW 200 conforms to IS 2645:2003 for integral waterproofing compounds.

Balcony waterproofing quantity calculator

Enter the floor size and the upturn to see the membrane and tile adhesive needed. Quantities only.

Eight mistakes that make a balcony leak

1. Tiling straight onto the slab. Tiles and grout are not waterproofing. Without a membrane under them, water reaches the slab through the joints.
2. Stopping the membrane at the floor. It has to turn up the walls and the door threshold, over a coving. A flat edge is where water gets behind it.
3. No flood test. A leak found after tiling means breaking the floor. Test before covering.
4. Slope towards the door. Water must run to the outlet. A back-fall sends it into the room.
5. Leaving the railing posts and pipes. Every post and pipe through the floor is a hole in the membrane until it is grouted and sealed.
6. Grouting the wall joint. The joint between floor tiles and wall moves. It takes a flexible sealant, not rigid grout.
7. Tiles in plain cement mortar outdoors. Balcony tiles heat and cool every day. They need a polymer adhesive that can move with them.
8. Filling a planter with no drain or protection. Standing water and garden tools both defeat a membrane that was never protected.

Balcony and podium waterproofing questions and answers