Knowledge Hub
Insulation & Waterproofing
Permanent solutions against humidity, with high-durability materials and 18 years of experience.
See the serviceQuick answers
Why is my roof leaking when it has been waterproofed?Water rarely comes through the middle of a roof. It gets in where the waterproofing is interrupted: seams, the corner with the parapet, and the bases of posts, pipes and drains.Polyurethane foam or a liquid membrane: what's the difference?A liquid membrane keeps water out. Polyurethane foam insulates against heat and cold and keeps water out too, but it can't stand the sun and needs a protective coat on top.Can an old bitumen membrane be patched, or does it have to come off?If it is still stuck down and only seams or corners have opened, it can be repaired locally. If it has come loose, blistered or wrinkled over a large area, it all comes off before anything new goes on.Is it worth making my roof white? Does it really keep the home cooler?A white waterproof coating reflects much of the sun, so the roof and the floor below heat up less. It doesn't replace insulation, and it needs renewing once it gets dirty and worn.Can a balcony be waterproofed without breaking up the tiles?Often, yes: if the tiles are firmly stuck, they can be cleaned and covered with a waterproof coating. Any loose ones must come up first, because nothing holds on a crumbling base.Water pools on my roof after rain. Is that a problem?Yes. Water that sits in one place for days wears the waterproofing faster and finds every weak spot. The usual causes are hollows, poor falls, or blocked or worn drains.My metal roof leaks and gets scorching in summer. What can be done?Water usually gets in at the screws, the joints between sheets and the corner with the wall. Spray polyurethane foam with a white coat closes those spots and insulates against the heat.The flat above the pilotis has a cold floor. Can it be insulated?Yes, from below: the pilotis ceiling is the floor of the flat. It can be sprayed with polyurethane foam in one continuous layer, without touching anything inside the home.Does my roof need a new screed before it is insulated?Not always. A new screed goes down when the roof has hollows or poor falls, or after old layers are stripped. On a roof that is walked on, a screed can also go on top to protect the insulation.
Guides
4 partsInsulation
Spray Polyurethane Foam: Flat Roofs, Metal Roofs and Pilotis Ceilings
What spray polyurethane foam is, where it fits, how the surface is prepared, how the awkward spots are sprayed and what has to cover it. With examples from real jobs.
Read the full guide
4 partsInsulation
Roof Waterproofing & Insulation: The Complete Guide
Why your roof leaks, which waterproofing systems exist, and how insulation cuts your energy bills. In four parts.
Read the full guide
4 partsInsulation
Rising Damp: The Complete Guide
Rising damp can silently damage your home's foundations and walls. In four parts, we explain what it is, how to spot it, and how to fix it for good.
Read the full guideTerms
Bitumen membraneWaterproofing that comes in rolls of reinforced bitumen. It is torched onto the roof in sheets that overlap at the seams.Cool roof coatingA white or very light top coat that reflects much of the sun's radiation, so the roof and the floor below heat up less.Efflorescence (salt deposits)A white, powdery or crystalline crust on the surface of a wall. It is salts carried by water through the masonry, left behind when the water evaporates.Elastomeric waterproof coatingA thick, rubbery waterproof paint for flat roofs, parapets and roofs. It stretches without cracking as the building expands and bridges hairline cracks.External wall insulation (ETICS)An external insulation system: insulation boards are glued and fixed to the outside walls, then covered with reinforced render and a finishing coat.Falls (drainage slope)The gentle slope built into flat roofs, balconies and bathroom floors so water runs to the drain or gutter instead of pooling.Flat roof (roof terrace)The flat concrete roof on top of a building. It is the most common kind of roof in Greece and the part that takes the most sun and rain.Floor drainThe outlet in a floor where water drains away on roofs, balconies and in bathrooms, with a grate on top and usually a trap below.Gutter and downpipeThe channel and pipe that collect rainwater from a roof and carry it down to the ground or the drains.Inspection pitA small chamber in the ground with a cover, where drain or rainwater pipes meet and can be checked and cleared.Liquid waterproofing membraneA waterproofing product applied as a liquid by roller, brush or spray. Once dry it forms one continuous, flexible membrane with no seams.Metal roof sheetingMetal sheets, flat or profiled, used for roofs and sheds. Light and quick to fit, but they get very hot and rust at the screws and cut edges.ParapetThe low wall around the edge of a flat roof or balcony. The joint between it and the floor is one of the most common places for leaks.Pilotis (open ground floor)The open ground floor under a block of flats, standing on columns with no walls, usually used for parking or as the entrance.Pressure washingCleaning a surface with a strong jet of water from a machine. Before waterproofing, insulation or painting, it removes dust, dirt, lichen and loose material so the new layer bonds well.PrimerThe thin first coat that goes on before the main material. It binds dust, seals the pores and helps paint or waterproofing stick firmly.Reinforcement meshA mesh or fabric, usually glass fibre or polyester, set into render, a coating or liquid waterproofing to hold it together and stop cracks from opening.Rising dampMoisture from the ground that climbs up inside walls through the pores of the materials. It shows as stains, blown render and salts at the foot of walls.ScreedA layer of sand-and-cement mix or lightweight concrete poured over the slab to create falls and a solid surface for the next material.Spray polyurethane foamA foam sprayed on as a liquid that expands on the spot and sets into one seamless layer. It insulates against heat and cold and closes cracks and joints.TarA black bitumen-based material spread hot or as a liquid emulsion. It seals the pores of concrete and keeps water out.Thermal bridgeA spot in a building where heat and cold pass more easily than through the rest of the wall or slab, such as columns, beams and the edges of a slab.Thermal insulationA layer of material that lets heat through only slowly, so a home keeps its warmth in winter and stays cool in summer.Tiled roofA pitched roof covered with clay tiles, on a timber frame or a concrete slab. The real waterproofing sits underneath, in the layer below the tiles.WaterproofingThe work and materials that stop water getting through on flat roofs, balconies, bathrooms, basements, planters and tanks.
Jobs in this category
All jobs
Insulation
Apartment Terrace Waterproofed with a White Membrane
A worn, cracked terrace was cleaned and primed, its cracks were sealed, and it was coated with a white liquid waterproofing membrane.
See the job step by step
Insulation
Roof Insulated with Spray Polyurethane Foam and a New Screed
A bare roof slab was sprayed with polyurethane foam, given a coat of tar, and covered with a new screed poured by a concrete pump.
See the job step by step
Insulation
Waterproofing a Planter on a Terrace
A built-in planter was emptied of plants and soil, cleaned, and coated with a white waterproofing layer on the floor and walls.
See the job step by step