How to Waterproof a Roof Professionally: The Complete Resina Color System

Picture yourself standing on the roof of an industrial building, a block of flats, or a private villa. You look down and see the substrate: a crack here, a dark patch there where water has sat too long, a corner of old membrane that has started to lift. You already know what it means — water ingress, damp, costly remedial work. And every year that passes, the problem worsens.

For more than 40 years, Resina Color has worked side by side with professionals, building contractors and applicators to solve precisely this problem. Not with improvised fixes, but with a system of products that has been studied and tested in the field, designed to deliver reliable results whilst cutting site time and set-up costs compared with traditional methods.

In this article we present the complete system for roof waterproofing and insulation: four products that work in synergy, each with a precise role, for a lasting, professional result.

Why Traditional Bituminous Membranes Are No Longer Enough

Anyone who works in the sector knows it well: the bituminous membrane has been the reference solution for decades. But it has concrete limitations that weigh heavily on site today.

Consider the reality: to apply a bituminous membrane you need open flames, long laying times, an additional protective layer (paving, gravel, or similar), and the set-up costs are considerable. If the substrate already has old membranes or bituminous treatments, the preparation work becomes even more complex.

The Resina Color system turns this logic on its head. No flames. No additional protective layers. Water-based products, applicable by roller or spatula, with contained drying times and an application cycle that an experienced professional can manage efficiently, even on large surfaces.

The System’s Products: Each in Its Right Place

The secret to waterproofing that endures over time is not a single miracle product. It is a system, where each phase prepares and enhances the next. Here are the four key players.

1. H95 Imprimitura — The Invisible Foundation

Before applying any waterproofing coating, the substrate must be consolidated. If it is porous, friable, or has areas of detachment, the final product will not adhere correctly, and within a few years all the work will need to be repeated.

H95 Imprimitura is a water-based, solvent-free primer formulated with micronised acrylic resins. These resins, owing to their very small particle size, penetrate deeply into the substrate, consolidating it from within. The result is a compact surface, ready to anchor the subsequent application cycle.

It is used on concrete, reinforced concrete, and absorbent surfaces in general. It also has a secondary function that is very useful on site: it can be employed as a dust binder for concrete floors.

Key technical data: theoretical yield 26 m²/litre, overcoating time 4–5 hours, very low VOC (5 g/L). An eco-compatible product with no compromise on performance.

2. R25 Primer W — The Bonding Agent That Makes the Difference

R25 Primer W is the second component of the system. It is a pigmented, water-based primer with acrylic resins of high saponification resistance (meaning excellent resistance to the alkalinity of the substrate), available in oxide red — the characteristic colour that visually marks areas already treated.

Its role is twofold and fundamental. First, it seals the substrate and further improves the adhesion of the waterproofing cycle. Second, if the cycle includes the use of fibreglass mat (a 300 g/m² fibreglass reinforcement mesh that mechanically strengthens the waterproofing), R25 is also applied over the mat to bond it definitively to the substrate and enhance its performance.

A practical detail: the product is ready to use but can be diluted with water if required. This makes it flexible and adaptable to site conditions.

3. EcomirrorTetti — Waterproof and Reduce Energy Consumption

Here we enter the territory of genuine innovation. EcomirrorTetti is not simply a waterproofer: it is a Cool Roof product — a category of coatings that reflects solar radiation rather than absorbing it.

How does it work? The formulation contains hollow glass microspheres from 3M — tiny glass spheres that are hollow inside — which create a thermo-reflective layer. This means two things: high solar reflectance (the roof reflects sunlight back rather than heating up) and reduced thermal conductivity (less heat passes from the outside to the interior of the building).

For a building contractor working on industrial buildings, warehouses, or residential properties, this product represents a concrete selling point to the end client: excellent waterproofing plus measurable energy savings on summer consumption, with no significant additional costs compared with a standard waterproofer.

UV resistant, applicable on concrete, pre-existing bituminous membranes, and galvanised sheet metal. Yield: approximately 1.1 m²/litre at 500 microns dry film thickness.

4. ResinGuaina — Maximum Resistance Where It Matters

When a roof is subject to heavy foot traffic — walkable surfaces, technical access areas, frequently used terraces — a product is needed that can withstand mechanical wear as well as water.

ResinGuaina is a thick, elastic, waterproof liquid membrane based on internally plasticised acrylic elastomeric resins, dilutable in water. Its distinguishing characteristic is its extremely high resistance to foot traffic wear, making it suitable even for surfaces subject to frequent use.

There is another aspect worth highlighting for professionals: ResinGuaina is certified for the encapsulation of asbestos (Certification ECOS No. 1794, 03/06/1996). This means that in the presence of fibre-cement sheets containing asbestos, removal is not necessary — with everything that entails in terms of costs, procedures, and disposal. The membrane is applied over the sheets, encapsulates the fibres, and makes them permanently safe.

Applicable by roller (with 10–15% water dilution) or spatula (without dilution). Yield: 1.1 m²/litre at 500 microns dry film thickness.

The Application Cycle: Step by Step

A good result begins with thorough preparation. Before starting any intervention, it is always advisable to inspect the roof condition with a qualified technician: check for water ingress points, identify areas of standing water, and remove dust, efflorescence (the typical white salt deposits) and any loose or detaching material.