Waterproofing materials: what suits your roof, bathroom or tank, and how to spot fakes
Ask three contractors about waterproofing your roof and you get three answers: membrane rolls, spray foam, paint-on coating. Each says their material is the answer. And after the job is done, you cannot tell whether the material applied is the one you paid for, or a cheap copy that cracks after two summers.
This guide explains the common waterproofing materials used in Saudi Arabia and where each one works. It includes three tools: a guide that suggests the right material for your surface type, a visual checker that helps you tell genuine epoxy and SBS membranes from poor ones, and a general checklist inspired by the Saudi Building Code to review your building.
What are waterproofing materials, and what do the tools give you?
Waterproofing materials are layers that stop water reaching the concrete, the steel reinforcement and the ceilings. They differ from thermal insulation, which reduces heat transfer, although some materials, such as polyurethane foam, do both.
The three Kashf tools:
- Insulation Materials Guide: you choose the surface type and it suggests suitable materials, with the advantage of each.
- Insulation Material Authenticity Checker: a visual comparison of the signs of genuine and imitation or poor material, for epoxy coating and SBS bitumen membrane.
- General Checklist Inspired by the Saudi Building Code: 6 items you tick when they are in place and confirmed, so you know what needs review.
Who are these tools for?
- Anyone building a house who wants to understand what the contractor will apply.
- Anyone re-waterproofing an old roof after rain leaks.
- Anyone renovating a bathroom or kitchen who wants proper waterproofing under the tiles.
- Tank owners who need a lining that is safe for drinking water.
- Anyone taking over finished waterproofing work who wants to check the material.
When should you use them?
- Before asking for quotes: to know the right material and compare quotes on the same basis.
- When materials arrive on site: to check containers and rolls before they are opened.
- During and after the work: to review color, thickness and welded seams.
- Before the rainy season or after a leak: to review the building's overall waterproofing.
Where do you use them?
The materials guide and the code checklist are in the Tools Hub, and the authenticity checker has its own page. All of them work on a phone, so take them to the roof or the job site and compare what is in front of you with the signs. They can be used anywhere; the checklist is based on the Saudi code, but its items are general good practice.
What do you need before you start?
- The type of surface you want to waterproof: a concrete roof, metal sheets, a bathroom floor, a tank or a façade.
- The material containers or rolls, or photos of them, if the material has arrived.
- The contractor's technical proposal, with the material name, thickness and number of layers.
- Access to the roof to see its slopes and drainage.
Tools and how to use them, step by step
Insulation Materials Guide
A drop-down list of surface types. For each type it shows the suggested materials and why:
- Exposed concrete roof: bitumen membrane rolls laid in overlapping layers with a UV-protection layer, and polymer-cement waterproofing as an extra or repair layer.
- Roof covered with metal or corrugated sheets: spray polyurethane foam that covers the joints between sheets, with flexible acrylic coatings on top for protection.
- Bathroom and kitchen floors: flexible cementitious waterproofing under the tiles, or epoxy for commercial kitchens and heavy use.
- Water tank (underground or rooftop): only epoxy made for, and safe in, contact with drinking water.
- Façades and exterior walls: flexible elastomeric acrylic coatings that cope with wall movement and sunlight.
Steps for correct use
- Open the guide
Go to the Insulation Materials Guide. You will see a "Surface type" list with 5 options.
- Choose the surface type
Pick the one closest to your case. An exposed concrete roof is different from a tiled roof. If you have more than one type, such as a roof and a tank, choose each one separately.
- Read the material cards
One or two cards appear, each with the material name and why it suits the surface. Note the material name so you can ask for it by name in quotes.
- Compare with the contractor's proposal
If the contractor suggests a different material, ask why. There may be a sound technical reason, such as the condition of old waterproofing or tiles on top of the roof.
How to read the result
- One suggested material: as for tanks and façades. The suggestion is specific here. For a tank in particular, accept nothing that is not made for drinking water.
- Two suggested materials: the first is usually the main layer, and the second is a complement or an alternative for certain cases, such as repair over old waterproofing or heavy use.
The suggestion is a starting point. The final choice depends on the real condition of the surface, any old waterproofing, the slopes, and what will be placed on top.
Insulation Material Authenticity Checker
A visual comparison page with two tabs: Epoxy coating and SBS bitumen membrane. Each material has two side-by-side cards, "Signs of genuine material" and "Signs of imitation or poor material", each with 5 signs covering color, thickness, texture or flexibility, smell or welding, and the packaging details.
Examples: genuine epoxy has a uniform color after curing, a hard surface that resists a fingernail scratch, and a sharp smell only while mixing that fades after curing. A genuine SBS membrane has an even surface finish, a constant thickness printed on the wrapper, flexibility when unrolled without cracking, and a uniform weld without bubbles.
The tool does not calculate a result or save data. It is a reference to compare with what you see.
AI label reading: below the guide, a section called "Photograph the product label to read it with AI" reads the brand, product name, printed specifications, quoted standards, batch number, and production and expiry dates. It works out the shelf-life status from the date it reads, and compares the label elements with what the page explains. It does not judge whether any product is genuine; if it cannot verify something, it says so. This section only appears when AI analysis is switched on for the site. If it is unavailable or reaches its limit, the page keeps working as normal, with a small note.
Steps for correct use
- Choose the material
Open the Insulation Material Authenticity Checker and tap the right tab: "Epoxy coating" or "SBS bitumen membrane".
- Check the packaging before opening
Compare the wrapper or container with the last sign: the manufacturer's name, product type, thickness and a batch number that is printed, not a handwritten sticker. Photograph it before use.
- Check during application
With SBS rolls, unroll a section and watch its flexibility, and look at the weld at the edges. With epoxy, notice the smell while mixing and whether the layer is even.
- Check after curing
Once the curing time set by the manufacturer has passed, compare color, texture and scratch resistance with the signs, and note any difference to discuss with the installer.
- Photograph the label (optional)
Photograph the label straight on, close up and without glare (up to two photos: front and back), then tap "Analyze photo" in the AI section.
How to read the result
- Most of your observations match the "genuine" card: a good first sign. Keep the photos and the batch number.
- One or two observations from the "imitation or poor" card: the cause may be poor workmanship rather than a fake, such as epoxy mixed wrongly or membrane overheated. Talk to the installer before the work continues.
- Many observations from the "imitation or poor" card: stop the work and ask the supplier for the product's certificate of conformity, or get a technical opinion.
Visual and touch signs are only a first screening and do not replace laboratory testing. To confirm a material meets a specific standard, ask the relevant authority or ask the supplier for its certificate of conformity.
- Label reading: the data read, the shelf-life status and the label elements (visible / not visible / unclear). To confirm authenticity, ask for an official invoice from a known supplier and check with the brand's authorized agent.
General Checklist Inspired by the Saudi Building Code
A self-check list of 6 general waterproofing items, inspired by the Saudi Building Code (SBC) requirements:
- A complete waterproofing layer on the roof, not partial or old and damaged.
- A clear roof slope that drains rain and does not let it pool.
- Structural expansion joints that are properly sealed.
- Foundations protected against rising ground moisture.
- An underground tank not in contact with damp soil or a source of contamination.
- No visible cracks in the exterior walls or the roof.
All items start unticked. Tick only what is in place and confirmed at your property; any item you leave unticked counts as unconfirmed. The list does not prove code compliance; compliance is decided by licensed engineers and the relevant authorities.
Steps for correct use
- Open the checklist
Go to the general checklist. You will see 6 unticked items and a bar showing "6 unconfirmed points of 6".
- Tick only what is confirmed
Tick an item if you have seen it yourself or have proof, such as construction photos, drawings or a report. "I think it's there" is not enough to tick it.
- Watch the counter
Each tick lowers the number of unconfirmed points. The result appears after your first tick or untick.
- Read the result and set priorities
Write down the unconfirmed items and start with the most serious for your case. For example, the roof before the rainy season, or the tank if it is close to a drain.
How to read the result
- "All items of the general checklist are confirmed": all six items are in place according to your answers. This is not official code compliance, and routine inspection is still useful.
- "Some items are unconfirmed — need review" (1 or 2 items): review these items with a technical team to assess their real effect.
- "Many items unconfirmed" (3 or more): the chance of future damp and leak problems is higher. Have the building fully inspected to set priorities before any further finishing.
Any structural crack or settlement needs assessment by a licensed structural engineer, not a waterproofing technician.
Types of waterproofing materials: where each one works
Bitumen membranes
Rolls of polymer-modified bitumen, such as SBS. They are laid on the roof and torch-welded with overlaps between rolls. They suit concrete roofs and need protection from the sun, either a mineral surface finish or tiles on top. Their weak points are the seams, corners and details around pipes and openings.
Flexible cementitious and polymer coatings
A two-part material, cement plus polymer, applied by brush or trowel. Common in bathrooms and kitchens under tiles, and for repairs over old waterproofing. It is easy to apply on uneven surfaces and corners.
Epoxy
A hard coating that resists water and chemicals. It is used inside tanks, provided it is a type made for drinking water, and on heavy-use floors.
Spray polyurethane foam
A foam sprayed as a liquid that expands and hardens. It provides both thermal and waterproof insulation and fills joints, so it suits metal-sheet roofs and roofs with many details. It needs a UV-protection layer on top.
Flexible acrylic coatings
A layer that stretches and shrinks with wall movement. It is used on façades and as a protective layer over foam. On its own it is not enough waterproofing for a concrete roof where water pools.
Flood testing and workmanship details in the Saudi climate
A good material is not enough if the workmanship is poor. Most roof leaks technicians see start at the details, not in the middle of the layer:
- Slopes: a roof without slope traps water on the waterproofing for days after rain.
- Corners and upstands: the waterproofing must run far enough up the surrounding parapet wall.
- Around drains and pipes: this is where gaps are most common.
- Expansion joints: Saudi summer heat makes concrete move, so rigid layers crack over the joints.
Flood test: after waterproofing a roof or bathroom floor and before tiling, the drain is plugged and the surface flooded for long enough, usually 24 to 48 hours, while the ceilings below are watched. Ask your contractor for this test and photograph it.
For the official code requirements, see the Saudi Building Code website.
Common mistakes that spoil the result
- Choosing on price alone: the difference in material price is small compared with re-waterproofing and repairing ceilings.
- Waterproofing over a damp or dirty surface: it stops adhesion, so the layer blisters and comes away.
- Using a general product inside a drinking water tank: a risk to water safety.
- Leaving membranes or foam exposed to the sun: UV rays weaken the material quickly.
- Judging authenticity by smell alone: smell is one sign out of five, and heat and ventilation affect it.
- Ticking checklist items by guesswork: it gives you false reassurance.
- Tiling before the flood test: any fault found afterwards means breaking the tiles.
Honest limits of the tools
- The materials guide suggests common materials for each surface type. It cannot see your surface, its old waterproofing or what sits on top.
- The authenticity checker compares general visual and touch signs for two materials only, epoxy and SBS. It does not replace laboratory testing or a certificate of conformity from the supplier.
- The general checklist issues no certificate and does not prove compliance with the Saudi Building Code. Compliance and approval are decided by the relevant authorities and licensed engineers.
- None of the tools locates an existing leak. If you have an actual leak, the first step is to find its source.
When do you need a leak detection technician?
- You have a leak or damp stains on the ceiling after rain, and you want to know the source before re-waterproofing.
- The general checklist shows 3 or more unconfirmed items.
- You noticed signs of poor material during or after the work.
- You want a drinking water tank lined with a safe, suitable material.
Kashf starts by locating the source of the damp with a thermal camera before any work, then applies the right waterproofing. The materials Kashf uses in its projects come from suppliers it checks directly, and the written warranty card attached to each waterproofing project states the material type and warranty period. This is a commercial warranty from Kashf, not an accreditation from an official body. Book a roof inspection and waterproofing, tank waterproofing, or bathroom and kitchen waterproofing. These services are available in Saudi Arabia only.
Frequently asked questions
Which waterproofing material should I use for my roof?
No single material suits every roof. Bitumen membranes are common for exposed concrete roofs, spray foam suits metal roofs and roofs with many details, and flexible cementitious coatings suit repairs. The choice depends on the roof's condition, any old waterproofing, and what will go on top.
How do I know the waterproofing materials my contractor brought are genuine?
Check the container or roll before it is opened: the manufacturer's name, product type, thickness and batch number should be clearly printed. Then compare color, thickness and flexibility or hardness with the signs in the authenticity checker. If in doubt, ask the supplier for the product's certificate of conformity.
Is spray foam waterproofing or thermal insulation?
Spray polyurethane foam does both: it reduces heat transfer, and it covers joints and cracks so water cannot pass. But it needs a UV-protection layer on top, such as a flexible acrylic coating, or its surface breaks down in the sun.
What is the difference between waterproofing a bathroom before and after tiling?
Proper bathroom waterproofing goes under the tiles, on the floor and the lower walls, followed by a flood test before tiling. Products painted over tiles or into the grout are temporary or supplementary fixes, and they do not solve a leaking pipe or drain under the tiles.
Can any epoxy be used to waterproof a water tank?
No. Inside a drinking water tank you must use an epoxy made for, and safe in, contact with drinking water, and you should ask the supplier for proof. Ordinary industrial epoxy may not be safe for stored water.
How long does roof waterproofing last?
It depends on the material, the quality of workmanship, how well the layer is protected from the sun, and the slopes and drainage. Good, protected waterproofing lasts many years, while exposed or poorly applied work can fail within a few seasons. The warranty period is stated in the contract and warranty card.
Does the building code checklist on Kashf prove my house is compliant?
No. It is a general self-check list of 6 items inspired by the code's waterproofing requirements, to help you see what you have not yet confirmed. Official compliance is decided by licensed engineers and the relevant authorities.
Why is my new waterproofing blistering or bubbling?
Usually because of moisture trapped under the layer, meaning it was applied to a surface that was not dry, or because of uneven welding of membrane rolls, or a dirty surface that stopped adhesion. Bubbles are weak points that may crack later, so ask the installer to fix them.
Should I waterproof the roof before finding the source of the leak?
It is not advisable. The water in your ceiling may come from a supply or drain pipe inside the slab, or from a roof tank, not the roof itself. Find the source first with a thermal camera and an inspection, then choose the right treatment, so you do not pay for waterproofing that does not solve the problem.
Related services
On-site inspections are available in Saudi Arabia; the tools and guides work anywhere.
This guide is educational. It explains estimation tools that help you understand a situation and decide what to do next; confirming a leak and pinpointing it always requires an on-site inspection with instruments. Structural questions are for a licensed engineer to decide.