Knowledge Hub
Quick answers
Answers to the questions we get asked most, with examples from real jobs.
Insulation & Waterproofing
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.Asphalt membrane or liquid polyurethane: which is better for the roof terrace?Mineral-surfaced asphalt membrane offers superior mechanical resistance when the roof terrace is used frequently. Liquid polyurethane is lightweight, completely seamless, and seals perfectly around complex obstacles like solar water heaters, vent pipes, and corners.Can I add external wall insulation only on my balcony walls, without scaffolding the whole apartment building?Yes. Exterior walls facing your own balcony or terrace can be reached without scaffolding and insulated either with insulation boards and render or with sprayed polyurethane.Do solar water heaters, air conditioners and water tanks have to be removed to waterproof the roof?In most cases solar heaters and water tanks do not need to be disconnected. Air-conditioning units can be lifted onto blocks while liquid coatings or sprayed foam are worked right under the frames and around every support leg.How do you waterproof a flat roof that has solar panels or meets a tiled roof along one side?The old failed membrane is stripped from under the panels and along the tile edge, every support base is sealed individually, and the new waterproofing is carried right up to the tiled roof junction so runoff from the tiles cannot slip underneath.My built-in planter box on the terrace or by the pool is causing damp. How is it waterproofed from the inside?To waterproof a built-in planter properly, all plants and soil must be emptied out, the failed old lining removed, and new waterproof coats applied across the floor, the corners, the inside walls and around the drainage holes.Water leaks in around our roof skylight when it rains. Can the base be sealed without replacing the skylight?Most skylight leaks come not from the dome itself but from cracked mortar around its curb where it meets the roof slab. Breaking out the loose material and sealing the base with reinforced waterproof coating stops the leak without replacing the skylight.Damp on our ceiling shows up right under the terrace railings or columns. How are their bases sealed?Where metal railing posts or columns enter the floor or parapet, rigid mortar and tiles crack around them. A lasting repair means opening and cleaning the base, then sealing it with flexible waterproof coating reinforced with fabric that turns up onto the post.Our outdoor concrete stairs leak into the storage room or space underneath. How are the steps waterproofed?Outdoor stairs have many corners — treads, risers and the wall junction — where hairline cracks open up. After cleaning and surface preparation, brush-applied waterproof coats seal every step and landing as one continuous skin.Why does roof waterproofing need to go up the parapet walls, and what if the parapet render has cracked?If waterproofing stops flat on the floor, rainwater enters through the floor-to-wall corner or through cracked parapet render and runs underneath the membrane. Loose render on the parapets must be repaired first, and the waterproofing turned up the walls.How are concrete roof drainage channels and basins waterproofed so they don't leak?Drainage channels and concrete basins carry the heaviest water flow. They are cleaned down to sound concrete and coated in multiple waterproof layers across the floor, the side walls and right into the drain outlet.Our roof is covered with old paving slabs. Can waterproofing or polyurethane foam be applied over them?Yes, provided the slabs are firmly bedded. The surface is ground and pressure-washed, joints and post bases are sealed, and either a liquid waterproof membrane or sprayed polyurethane foam is applied directly on top.The white liquid membrane on our roof has gotten dirty and developed hairline cracks. How is it renewed?If the existing coating has not blistered or peeled away, the roof is washed thoroughly, cracks and vent pipe bases are sealed locally, and fresh waterproof coats are rolled across the floor and parapets.Can sprayed polyurethane foam be used on the exterior walls of a new build before plastering, or on an interior ceiling?Yes. On bare exterior walls of a building under construction, sprayed foam forms a seamless thermal blanket before rendering, while on interior ceilings or pilotis soffits it is sprayed from below and can be painted white.Pipes running along the base of our terrace wall are letting damp in. How can they be boxed in and waterproofed?When an old pipe cover on a terrace falls apart, a new box is built over the pipes, all joints with the wall and floor are sealed, and the entire box and surrounding tiles are coated with waterproof membrane.When insulating a bare roof slab from scratch, how are polyurethane foam, bitumen and pumped screed combined?The system can be built either with the insulation under the screed (polyurethane foam sprayed on the slab, a bitumen layer, then pumped screed on top) or over the new screed (pumped screed for falls, bitumen primer, then sprayed foam).On a leaking metal or corrugated roof, is sealing the joints and screws enough, or does it need a full coating?If the metal sheets themselves are sound, cleaning and sealing the parapet joint and every screw head is enough. If the whole surface is weathered or overheats in summer, a full reflective coating or sprayed polyurethane foam is applied.How do you insulate narrow rooftop passages around the stairhouse where water tends to pool?In tight passages between the stairhouse wall, parapets, railings and solar heaters where sheet membranes are awkward to lay, bitumen primer and sprayed polyurethane foam coat the floor and turn up the walls in one seamless layer.
Professional Painting
Can I just paint over a damp or mouldy wall?No. Paint hides the stain for a while, but if the damp is still there it comes back and takes the new paint with it. First find the cause, then scrape back and repair the wall.Why is the paint peeling off my walls?Usually because of damp, or because it went on over a surface that wasn't holding: dust, loose old layers, a glossy base. The fix is to remove whatever isn't holding, not to add another coat on top.After a fire, is a coat of paint enough to get rid of the black?No. The soot has to be cleaned off and a stain-blocking primer applied first, or it comes back through the new paint. Before anything else, check what the heat has loosened.A piece of plaster fell off the ceiling. What now?Keep the area underneath clear, as more plaster around it may be loose. Then find out why it fell, whether damp, a leak or rusting steel, before it is re-plastered and painted.I want new colours at home. Where do I start?A few colours repeated from room to room, one wall in a stronger shade if you want character, and a darker colour where walls get dirty easily. A strong old colour needs extra coats to cover.My ceiling has a rough textured finish. Can it be made smooth?Yes. Any loose parts are removed, the ceiling is skimmed smooth and then painted. A smooth ceiling collects less dust and is easier to repaint evenly.Can I refresh my kitchen by painting the walls, doors and cupboards without ripping out the units?Yes, as long as the cupboards and woodwork are structurally sound. With proper preparation, wall filling and repainting of cupboard doors and frames, a kitchen is transformed without stripping out the units.Our walls are painted a strong colour (lime green, blue, mint). How do you turn them pure white without the old shade showing through?To cover a strong or dark shade cleanly, any flaking paint is scraped first and repairs are filled and sanded, followed by successive coats of white with proper drying time in between until the colour is completely uniform.Spray painting vs roller in an apartment: when is a paint sprayer used and how is the furniture protected?Airless spray painting gives a very smooth, uniform finish across walls and ceilings, provided every piece of furniture, window frame and floor is completely masked in plastic sheeting and tape beforehand.The render on our apartment building's facade or side wall is blistering and falling. How is it repaired and painted from scaffolding?Scaffolding with safety netting is erected, all hollow and crumbling render is hacked off, edges and surfaces are rebuilt and filled, and the entire elevation is painted top-to-bottom with weather-resistant exterior paint.Our balcony parapet and walls keep peeling. What preparation is needed before repainting them?Simply painting over a peeling balcony parapet will not hold. All loose paint and crumbly render must be scraped off, the surface repaired and primed, and finished with exterior acrylic paint.Why do plaster and paint blister above and below windows, and how is that repaired?Around windows — at the lintel above, around the shutter box and beneath the marble sill — moisture often creeps in through exterior gaps or condensation. The damaged plaster is scraped back, filled, primed and repainted.What does a ground-floor shop or office with damp walls and a worn floor need to look clean and ready for use?In ground-floor shops and offices, damp along the base of the walls is treated by scraping back loose material, repairing and repainting, while a worn floor can be washed and coated with hard-wearing floor paint.I want one feature wall in a different colour in the living room or bedroom. How do you combine it with the other walls?A feature wall works best behind a fireplace, TV unit or bedhead, while the remaining walls stay white or very light so the room keeps its brightness and white doors and wardrobes stand out cleanly.Our exterior courtyard wall is shedding large pieces of render. How is it repaired with mesh so it doesn't crack again?All hollow render is hacked off, deep voids are patched, fibreglass reinforcing mesh is embedded into a continuous skim of repair mortar across the wall, and the surface is finished with exterior paint.What care is needed when repainting an older Athens apartment with high ceilings, interior wooden doors and built-in wardrobes?Older Athens apartments feature high ceilings with plaster mouldings, glazed double doors, tall built-in wardrobes and classic floors. They require careful taping along edges, crack repairs on the walls, and dedicated preparation for the woodwork.
Bathroom & Kitchen Renovations
What does a full bathroom renovation involve?Stripping back to the brick, new water and drain pipes, a floor sloped to the drain, rendering, tiles and finally the fixtures. Each stage is hidden under the next, so the order matters.Can my bathtub be replaced with a floor-level shower, with no step?Usually yes, as part of a renovation. The floor is rebuilt sloping to a drain or a channel, so the shower sits level with the bathroom. Whether the drainage fits underneath is decided on site.What needs doing to the walls before a new kitchen goes in?First the kitchen is drawn to the room's measurements. Then the old units come out, water and power points go where the drawing needs them, and the walls are plastered straight before the cabinets go up.Does an old bathroom always need a full renovation?Not always. If the tiles and pipes are sound, repairing the walls above the tiles and changing the fittings may be enough. With leaks, worn pipes or tiles coming loose, it needs a full one.Can new tiles go on top of the old ones?Sometimes, if the old ones are firmly stuck and flat. But the old pipes stay hidden underneath, and if some tiles are loose or sound hollow, they all have to come off.Is a concealed cistern worth it? And if it breaks, will the wall have to be broken?It saves space and makes cleaning easy. Its mechanism is usually reached through the flush plate opening, without breaking anything. It can only go in while the wall is open.Does a shower need waterproofing under the tiles?Tiles and grout are not watertight. On the floor and walls of a shower, a waterproofing layer under the tiles protects the wall and the flat below.I have a very narrow WC or tiny bathroom. What renovation choices make it comfortable and practical?In a narrow WC or small bathroom you gain valuable space by replacing an old tub with a shower, fitting a concealed cistern with a wall-hung toilet, and using light tiles or smooth white walls.How is a built-in wall niche made inside the shower, and at what stage of the bathroom renovation is it built?A built-in shower niche is formed at the bricklaying and plastering stage before tiling begins, waterproofed along with the shower walls, and lined with matching tiles so bottles sit neatly inside the wall.I want to brick up an interior doorway or wall opening between two rooms. How is it done so no joint shows?The opening is bricked up to the ceiling, plastered in two coats flush with the existing wall, filled and sanded across the joints, and the whole wall is painted so no trace of the old opening remains.When stripping an old floor, laying new tiles and repainting a flat, in what order is the work done?First the old flooring is broken out and the rubble bagged and cleared, then wall preparation and floor tiling (including skirtings) are completed, and the final coats of paint go on last.The bathroom walls and ceiling above the tiles are peeling from steam. How are they repaired, and when is a false ceiling used?If the bathroom tiles are still sound, the peeling walls and ceiling above them are scraped back, repaired and repainted. During a full renovation, a moisture-resistant plasterboard ceiling can also be fitted to hide pipes and house recessed lighting.
Wall Demolition
What does it mean to strip a bathroom or kitchen "back to the brick"?It means the tiles, render, fixtures and old pipes all come out until the bare masonry shows. The renovation then starts from a sound base, and you can see what the walls were hiding.Can I knock down a wall to join two rooms?It depends on whether the wall is load-bearing. Brick walls between concrete columns usually carry no load, but that is for an engineer to confirm. Structural elements are not touched without a design and a permit.Can I stay at home while the bathroom or kitchen is being stripped out?Yes, but it takes preparation: sealed doors against the dust, a plan for where you'll wash or cook, and patience with the noise and the breaks in water and power.What happens to the rubble from a strip-out? Where does it go?It is bagged inside the home, carried down with the shared areas protected, and has to end up with a licensed waste management scheme, not in the household bins.When do old terrace tiles or old roof membranes have to be stripped off completely before new waterproofing?When terrace tiles have lifted and cracked or water is trapped beneath torn, debonded roof membranes, stripping them back to a solid base is essential so the new waterproofing can bond properly.
Paving & Courtyards
The joints in my stone courtyard have gone dark. Does it need relaying?Not necessarily. If the stones are sound, the joints alone can be redone, which binds the floor together again and completely changes how it looks.The pavement outside my house has broken slabs and weeds. Patch it or redo it?If only a few slabs are broken, just those can be replaced. When most are broken and weeds grow everywhere, it usually makes more sense to redo the whole stretch, for example in new concrete.After rain, water sits on my balcony, mostly by the door. What's wrong?Usually the falls: the floor doesn't slope towards the drain, or it has hollows. If the drain is clear, the slope only changes if the layer under the tiles is redone.Weeds and moss grow between my paving slabs. Is pulling them out enough?For a while, yes, but they'll come back. They grow where joints have opened and damp lingers, so the lasting fix is to close the joints or redo the broken stretch.For a yard or sidewalk, which is better: concrete or slabs?There's no single right answer. Concrete gives one continuous surface with no joints for weeds. Slabs and stone look better and can be repaired piece by piece, but their joints need care.An old stone-paved courtyard has grown dark and its joints are worn. How can it be refreshed with new pointing without lifting the stones?When the flagstones themselves are solid, there is no need to lift them. The old darkened joints are raked out and cleaned, then repointed with fresh white or light mortar that seals the paving and brightens the whole courtyard.
Wooden Shutters, Doors & Pergolas
My wooden shutters are faded and peeling. Can they be saved or do they need replacing?If the wood underneath is sound, they can usually be saved: sanded back to clean wood, primed and painted, or given a clear finish. Wood that has rotted and gives under pressure needs repair or replacing.How can I tell my wooden pergola needs varnishing again?When the wood fades or greys, feels rough, opens small cracks or soaks up water instead of shedding it. The parts that take the full sun and rain need varnishing more often than the rest.Can I paint my shutters over the old paint without sanding?Only if the old paint is holding firmly everywhere. If it's peeling or cracked, the new coat will come off with it. Anything loose has to come off with a scraper and sanding first.Should I paint or varnish my wooden shutters and door?It depends on the wood and on what you want to see. Paint covers the wood and hides old repairs. Varnish lets the grain show, but it needs clean, sound wood underneath.My wood has gone grey and cracked. Does that mean it's rotten?Not necessarily. Greying and fine cracks are usually surface wear from the sun and come off with sanding. Rotten wood is soft, gives when you press it, or crumbles.How do you maintain a wooden rooftop pergola together with its trellis panels and wooden planter claddings?On a roof terrace, sun and wind dry out not only the main pergola beams but even faster the thin slats of trellis panels and wooden planter claddings. Cleaning and re-varnishing all the woodwork together keeps the timber protected.
Small Repairs & Odd Jobs
A crack has opened in my ceiling and I can see rusty steel. Is it dangerous?It means the reinforcement is rusting, usually because of water, and shouldn't be left. Local damage is repaired: clean, protect the steel, rebuild with repair mortar. If it is spreading or on a beam, call an engineer.Part of my wall is damaged. Is it enough to patch and paint just that spot?The patching is done on the spot, but it is better to paint the whole wall. New paint over a patch usually stands out from the old paint around it, however well the shade matches.I have a damp stain on my ceiling. Is painting over it enough?Only if the cause has stopped. The stain points to water from above (a roof, a bathroom, a pipe) or condensation. Deal with that first, then scrape anything blistered, fill, prime and paint.I fill a crack in the wall and it opens again. Why?Because the crack is moving and filler doesn't stretch. It usually sits where materials meet, on hollow plaster or over a deeper cause, so it needs mesh or a different repair.The plaster sounds hollow when I tap it. What does that mean?That the plaster has come away from the wall behind it, even if it doesn't show yet. It isn't filled over: it is removed back to a sound base and redone.The plumber and electrician opened up the walls. How are they closed so nothing shows?The chases are filled with plaster up to the wall's level, with mesh where a crack could open. Then filling, sanding, primer, and paint over the whole wall.A leak caused plaster to fall and left a hole in the ceiling. When and how should it be repaired so it doesn't fall again?First the leak above must be stopped. All loose plaster around the hole is then removed, any exposed rebar is treated against rust, and the patch is built back up with repair mortar, skimmed smooth and painted.Why does the wall paint and plaster blister and peel right next to a door or balcony door, and how is it fixed?Next to entrance doors, balcony doors and bathroom doors, walls often draw moisture from the threshold or frame joint. All loose paint is scraped back to sound plaster, filled smooth in layers, sanded and repainted.