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Mariseal 250

Maris Polymers Mariseal 250 is a single component permanent elastic liquid-applied polyurethane coating which cures to form a highly elastic seamless waterproofing membrane. This premium liquid coating is ideal for flat roofing systems (including green roofs), balcony waterproofing, decks, walkways and car parks. This waterproofing coating is based on pure elastomeric hydrophobic polyurethane resins which delivers superb mechanical, chemical, thermal, UV, and natural element resistance properties.

This highly permanent elastic liquid applied coating is cost effective and provides excellent waterproofing for a long period of time with an expected life time of at least 25 years if installed correctly. The cutting-edge technology used in Mariseal 250 allows this liquid-applied polyurethane coating to provide solutions where other liquid roofing systems fail. This includes applications with stagnating water, frost, humidity and extended exposure to the sun.

In A Rush? Order Mariseal 250 Now

Mariseal 250 is manufactured by Maris Polymers 1, who are a globally renowned for market leading, waterproofing products. Maris Polymers have been established for over 40 years and provide waterproofing systems in more than 70 countries.

Benefits Of Using A Mariseal 250 Liquid Waterproofing System

• Easy To Apply Using A Roller Or An Airless Spray

• Seamless Joint Free Finish

• Certified For 25 Years Expected Life (EOTA –DIBt)2.

• Natural Element Resistance Properties (frost and water resistant)

• Anti-Root Properties (suitable for green roofs, flowerbeds, planter boxes)

• Water Vapour Permeability Allowing The Surface To Breathe

• Excellent Thermal Resistance (it does not become soft over time)

• Excellent Resistance to UV Rays

• Cures By Reaction With Ground And Air Moisture

• Suitable for crack-bridging up to 2mm, even at -10° Celsius

• Can Be Used As A Liquid Applied Overlay On Flat Roofing Systems such Bitumen And Asphalt Felts

• Provided A High Level of Sun Reflectivity Which Helps Thermo-insulation

• Is A Cold Applied System, There Is No Need For Open Flames

• International Track Record Of Waterproofing Performance For More Than 15 Years

• Easy And Cost Effective Maintenance

• Repairs Can Be Carried Out Locally Even If Membrane Sustains Mechanical Damage

• Can Service Applications Which Require Pedestrian And Vehicular Access

• Can Maintain Mechanical Properties Over A Temperature Span Of Between -40° Celsius and 90° Celsius

• Can Be Applied In A Number Of Ways: wet on wet using a polyester fleece, base and topcoat method using polyester fleece or GFM, and as an unreinforced field area (all upstand and detail areas remain reinforced)

How To Apply Mariseal 250 To A Flat Roof

Mariseal 250 is a one component polyurethane membrane which is a tried and tested long lasting waterproofing solution for flat roofing. Before this cold applied system is applied the surface must be suitably prepared.

Preparing The Surface Of The Flat Roof For The Application Of The Liquid Applied Polyurethane Coating

Surface preparation is an extremely important part of the installation of any flat roofing system. By carrying out the correct preparation the durability and finish will be maximised. The surface must be clean, dry, structurally sound and free of any contamination. The reason for this is to ensure there is nothing which may be harmful to the adhesion of the membrane. The first step should be to sweep away any debris on the roof. Next, old, loose coatings, organic substances, dust, oils and fats must be removed by a grinding machine. Any surface irregularities must be rectified to leave a smooth surface. Finally, it must be ensured the surface is dry. The maximum moisture content of the surface should not exceed 5% and any new concrete substrates should be left to cure for at least 28 days.

IMPORTANT: The Surface Should Not Be Washed With Water.

Seal All Joints And Any Cracks In The Surface

For long lasting waterproofing all joints and any cracks in the surface must be sealed.

Sealing Joints: All expansion and control joints must be cleared of any residue,dust, or any form of contamination. If required joints should be widened. The prepared movement joint should have a depth of 10-15 mm. The width to depth ratio of the movement joint should be at a rate of approximately 2:1. The bottom of the joint should be sealed with PU 30 sealant. Next a stripe of Mariseal 250mm should be applied over the joint. This stripe should be 200mm wide directly over and inside the joint. A reinforcing fabric should be laid on top of this wet coating and pressed deep inside the joint. This fabric should be soaked with Mariseal 250 with the joint fully covered from the inside. The fabric should be completely saturated with Mariseal 250. Next a polyethylene cord the same size as the joint should be placed inside the joint pressing down on the saturated reinforcing fabric. Finally any remaining space in the joint should be filled with PU 30 sealant. Once this is done the joint should not be covered and left for between 12 and 18 hours to cure.

Sealing Cracks: Any cracks in the surface should be cleaned of residue, dust and any other kind of contamination. This includes hairline cracks. These cracks should be primed locally and left for 2 to 3 hours to dry. Any cracks which are not hairline should be filled with PU30 sealant. Then a stripe of Mariseal 250 in a 200m wide lap should be applied. Next, the crack should be covered with reinforcing fabric and then pressed to ensure it is soaked in Mariseal 250. Finally the fabric should be completely covered in Mariseal 250. Once this is done it should be left for 12 hours to cure.

Priming The Surface For The Application Of The Mariseal 250 Liquid Applied Polyurethane Coating

Mariseal Aqua Primer is suitable for a wide range of substrates. This ranges from very absorbent surfaces such as concrete, wood and cement screed. To typical flat roof systems like bituminous and asphalt felts. And non-absorbent surfaces such as ceramic tiles, old coatings and metal. Once the primer is applied across the substrate it should be left to cure in accordance to the technical instructions.

Applying The Mariseal 250 Cold Applied Liquid Waterproofing Membrane

Once the substrate is prepared and primed, this one component polyurethane membrane is ready to be applied. Once the the metal pail or barrel is open it should be well stirred then poured out onto the substrate. This cold applied liquid should now be rolled or brushed out until the full area which requires waterproofing is covered. This pure elastomeric hydrophobic polyurethane can also be applied using an airless spray. This can result in considerable savings in labour costs on larger areas such as commercial flat roofs.

It is important to use reinforcing fabric around problem areas such as soil vent pipes, plant machinery, 90 deg angles and wall to floor connections. This should be done by applying the reinforcing fabric when the Mariseal 250 waterproofing is still wet. The fabric should be pressed into the wet liquid applied coating until it is soaked. Then it should be covered with a coating of Mariseal 250.

It is advisable to reinforce the entire surface with reinforcing fabric. This should be done by suing 5 to 10 cm strips which are overlapping. After 12 -18 hours another layer of Mariseal 250 should be applied. This must be applied no later than 48 hours later. If the area being reinforced is particularly demanding a third layer of cold applied liquid Mariseal 250 should be applied.

A layer of Mariseal 250 should not be laid in a greater thickness of 0.6mm. For best results the temperature during application and curing should be between 5° Celsius and 35° Celsius. Low temperatures delay curing while high temperatures accelerate curing. In highly humid conditions the final finish may be affected.

Finishing The Application Of The Mariseal 250 One Component Polyurethane Membrane

For a colour stable and a chalking-free surface, one or two layers of Mariseal 400 top coat should be applied over the Mariseal 250 liquid applied polyurethane coating. The application of a Mariseal 400 top coat is especially important if the final colour desired is dark, such as red or green.

For a finish which is abrasion resistant such as a car park or walkway, two layers of mariseal 420 should be applied.

IMPORTANT: This sytem is slippery when wet. In order to avoid slipperiness during wet days, anti-slip aggregates should be sprinkled onto the liquid coating when it is still wet.

Flat Roof Repair With Mariseal 250

This waterproofing coating is also ideal for repairing isolated roof areas. It is a pure elastomeric hydrophobic polyurethane which is self-terminating. This means specific areas can be isolated. The area would need to be cleaned and cleared of any debris. Then primed locally with any cracks being filled with PU30 sealant. Next, Mariseal 250 can be applied to the area. After this reinforced fabric can be laid over the effected area and soaked in the Mariseal 250. Finally the reinforced fabric can be covered with a coat of Mariseal 250 to complete the repair. Mariseal 250 cures through reaction with ground and air moisture. This process normally completes within 12 hours. The method of repair used to fix a specific area is often referred to as a patch repair. These repairs can be carried out quickly and without disruption to the everyday working of the building. This makes Mariseal 250 an extremely cost effective solution for flat roof repairs.

Walkway Waterproofing With Mariseal 250

A further good illustration of the importance of the specification flexibility of liquid waterproofing  involves walkways. These types of projects are usually of a refurbishment nature, such as social flats and housing or balconies whose surfaces have simply worn out or have become too slippery to be safe. Typically, these works are carried out whilst the buildings are occupied and are subject to working around residents’ daily routines. Hence a fast-curing liquid is essential, so its installation causes the concerned properties minimum upheaval. In this instance the Mariseal 250 liquid waterproofing liquid can have a catalyst added to speed up curing time, sometimes as little as twenty minutes realistically, as any faster can compromise the working process required on any difficult areas. 

So, if the area was a concrete deck, the procedure would be to jet wash and dry the area, including upstands prior to Mariseal Aquaprimer being used at around 100/200 grams/m2. However, if the substrate is still slightly damp work can still carry on as the Aquaprimer absorbs any remaining moisture into itself as water forms part of the systems curing process. This can save the contractor much time. Once the primer has cured, a base coat of liquid is then installed. Normally upstand areas are installed first. The upstand and any change of direction areas must always be reinforced. The base coat of the field area can then be installed with or without reinforcement if specified.

A further topcoat is then coated, either whilst the base liquid is still wet and fresh and has been coaxed through the reinforcing fleece if specified via using a short haired roller. This method is called "Wet on Wet". Or waiting for the base coat to dry and installing a topcoat in the same way again, with added catalyst whilst broadcasting quartz or another hard-wearing anti slip material into it whilst still wet. This is often called a two-coat system. Both methods offer up a fast, hassle-free solution to promptly refurbish walkway areas.

The situation is much the same regarding balcony areas. The difference may be the addition of pavers or decking. If this is the case, you should either apply a thicker coating of liquid or use a 300-gram fleece between the liquid coated deck and any contact areas with the balcony pavers or decking. At no point should the liquid waterproofing coating be punctured to accommodate this build up. Although if this happens liquid waterproofing is very easy to repair. Simply gently abrade the surrounding area of the damage and coat over. Unlike single ply, you would see no unsightly patches and the surface appearance is not compromised.

Refurbished Flat Roof Specification

A typical outline specification on a refurbished single ply/asphalt/bitumen felt or concrete would be.

1. Clean and dry deck

2. Prime with relevant primer. A peel test is always recommended regardless.

3. Install liquid onto upstand and detail areas coming onto field area 150mm. Reinforcement must always be used

4. Install base layer integrating reinforcement if specified. If wet on wet method, then ensure reinforcement is seeing base coat coming through by lightly rolling

5. Install topcoat. Immediately if wet on wet system is being used. Or if a two-coat system is being used once base coat and reinforcement coat is fully cured.

6. If a walkway area is required, tape off relevant area and install thin coat of liquid. Broadcast quartz3 or other anti-slip material into this. When cured brush off loose particles

Note: adding a catalyst product is an option throughout

Walkway Refurbishment Specification

A typical walkway refurbishment specification would be:

1. Clean and dry deck

2. Prime with relevant primer. A peel test is always recommended regardless.

3. Install liquid onto upstand, balustrade, and any detail areas. Ensure these come 150mm onto horizontal area. These areas must always be reinforced.

4. Install base layer integrating reinforcement if specified. If wet on wet method, then ensure reinforcement is seeing base coat coming through by lightly rolling

5. Install topcoat. Immediately if wet on wet system is being used. Or if a two-coat system is being used once base coat and reinforcement coat is fully cured.

6. When the topcoat is still wet broadcast quartz or other anti-slip material into it. When cured sweep away any loose material. Or ensure 300-gram fleece is laid prior to non-penetrating decking or paving is laid.

Are There Any Systems Which Perform Better Than Mariseal 250?

In our experience Mariseal 250 is one of the best performing liquid roofing products on the market. However, we have experienced some slight drawbacks with this product. One is the cure time in extremely high or low temperature. And the other is the use of this product on complex detailing. Maris Detail can be used with Mariseal 250 for detailing but this requires using 2 products for one roof.

A product we have found which overcomes all of these problems is Starflex Mono Tix 100. This product performs exceptionally in all conditions. It also offers excellent anti-slump properties making it ideal for complex detailing. The real beauty of this product is it does not need to be combined with any other system and has excellent elasticity due to polyurea infusion.

Need Any Further Information Regarding Mariseal 250?

If you would like any further information or a quote to supply or install Mariseal 250 please contact us or call us now on 01277 375 511. One of our friendly team of liquid waterproofing specialists will be delighted to help.

Frequently Asked Questions About Mariseal 250

How Long Does This System Take To Cure?

This system cures by reaction with ground and air moisture. This depends very much on the temperature. In hot weather it could be fully rain resistant, and able to cope with light traffic within hours. Final curing time is a maximum of 7 days (above varies considerably if catalyst is used).

What Colour Is This Waterproofing Product?

The available colours are dark and light grey. Dark grey RAL 7031 is the most popular UK colour, but a lighter grey RAL 7035 is available.

Is This Waterproofing System Fire Resistant?

This cold applied liquid system has the highest current fire rating for liquid waterproofing systems which is Brooft4.

Is This Waterproofing Coating Suitable For Green Roofs?

Yes, it is suitable for green roofs, flowerbeds, planter boxes. It is root resistant meaning it is an excellent choice of flat roofing system for those wanting roof gardens and green roofing systems.

Can This System Be Applied Direct To Concrete And Screed?

When applying this system to concrete or cement screeds the following steps should be followed. 1) The surface should be swept clean of any debris. 2) Any old, loose coatings, organic substances, dust, oils and fats must be removed by a grinding machine 3) All joints and cracks should be cleaned and sealed. 3) Primer should be applied.

Can This System Be Applied To A GRP Flat Roof?

Yes it can be applied over a GRP flat roof. Often this is possible without the need for primer, subject to a peel test.

What Is The Weight Of The Polyester Fleece Used?

There are two weights 65 g/m2 and 110 g/m2. Both are considered suitable for use with this system.

Is This System Suitable As A Walkway And Balcony System?

Yes, it is suitable to be used for both walkways and balcony waterproofing systems. Just like with flat roofing systems the mechanical properties of this product, it being a liquid applied highly permanent elastic membrane and having an excellent life expectancy, make it an excellent system for walkways and balconies. During the ground and air moisture curing process, quartz or aggregates can be added to provide anti-slip properties. Once the coat is cured any loose material is brushed away and either a clear coat (Maritrans) or a further thin topcoat of Mariseal 250 can be added. An accelerator liquid can also be added if faster curing is required. This would typically be required if refurbishment of public and social housing walkways is taking place.

Is Mariseal 250 A Suitable Alternative To PMMA?

Yes, it is is a suitable alternative to PMMA. Mariseal 250 is fast curing and traffic resistant. The odour is also much less noticeable than PMMA’s, which can be overbearing at times.

Is This A Simple System To Install?

Yes. Typically, deck preparation, primer (when required), base coat and topcoat with fleece in between, but not essential. Sometimes if a lesser life expectancy is required, just a generous single coat (1.2kg/m2 and above) will be fine.

Can This System Be Installed In Wet Conditions?

It is never a good idea to install any cold liquid in wet conditions.

Can This System Be Applied Onto Frost Or Freezing Substrate?

It is bad roofing practice to install a cold liquid onto a deck that is frosted or is close to freezing. Refer to data sheet for exact details.

Is Mariseal 250 Suitable For Residential Applications?

Yes it is an excellent waterproofing system. It provides mechanical, chemical, thermal, UV and natural element resistance properties. This makes it ideal for residential projects including waterproofing roofs and balconies.

Does Mariseal 250 Cope Well With Thermal Movement?

Yes, it is a highly permanent elastic waterproofing membrane. It provides excellent thermal resistance over long periods of time. It also has natural element resistance properties.

How Do You Store Mariseal 250?

Pails should be stored in dry and cool rooms for up to 12 months. The one component polyurethane membrane should be protected against moisture and direct sunlight. Storage temperature: 5° to 30°Celsius. Products should remain in their original, unopened containers, bearing the manufacturers name, product designation, batch number and application precaution labels.

Can Mariseal 250 Be Applied Over A Damaged Flat Roof?

Yes, in most circumstances this liquid applied polyurethane coating can be applied over a damaged flat roof. In most cases the flat roof will need to be cleaned, the surface suitably prepared and primed before Mariseal 250 can be applied.

Is This System Suitable For Concrete Constructions?

Yes, this system is suitable for concrete constructions.  It has proven itself as a waterproofing system for bridges, decks, tunnels, car parks.

How Many Years Does This Cold Applied Liquid Flat Roofing System Roof Last?

If installed correctly between 10 and 25 years depending on the liquid thickness.

Is This System Self-Terminating?

Yes. You do not have to cut a chase area or use any termination bar or sealant.

Can This Liquid System Be Used Under Tile Wet Areas?

Yes this system is proven to be effectively used when applied under tile wet areas.

Get In Touch About Mariseal 250

If you would like any further information or a quote to supply or install Mariseal 250 please contact us or call us now on 01277 375 511. One of our friendly team of liquid waterproofing specialists will be delighted to help.