How do I work with Flexim?

Flexim is supplied in a choice of pack sizes: large packs contain 10 strips of Flexim whilst small packs contain 5 strips. We recommend cutting open the required strips and removing these from the packaging before you go out onto the roof. Below is a step-by-step description.

  1. Remove the top cover from the packaging and place this upside down next to the bottom.
  2. Cut open the required number of strips using a cutting knife.
  3. Take the Flexim strips out of the plastic packaging and place the strips in the cover. Use 1 latex glove for this.
  4. Place the bottom on top of the cover and take the Flexim product with you onto the roof in the box packaging.
  5. Put on 2 latex gloves and then knead the Flexim strips firmly onto the uppermost row of roofing tiles. Repeat this until all of the strips of Flexim have been placed on the roofing tiles.
  6. Take the gloves off and press the ridge tile firmly into the Flexim with your clean, bare hands. Make sure the ridge tile is not pressed all the way down to the ridge board, but that it “hovers” at least 1 cm above this. If you don’t have a ridge board, then make sure there is sufficient space between the ridge tile and the uppermost row of roofing tiles.
  7. Pull on one latex glove and cut off the excess Flexim using a spatula or a knife.
  8. Spread the Flexim smooth until you have obtained an even finish.

Why must my ridge tile be placed ``hovering``?

Flexim is a flexible paste that accommodates the expansion and contraction of the roof. A roof is always in motion and the entire roof structure has to deal with this movement, including the ridge tiles.

For this reason, it is extremely important that the ridge tiles are not pressed tight against the ridge board, but that they “hover” above the ridge board. When doing mechanical anchoring with stainless steel screws, the ridge tile must also lie at least 1 cm above the ridge board. This allows any movement to be accommodated optimally by the Flexim product.

How long can I keep Flexim?

In a closed, undamaged package – 2 years.

However, if a strip has already been cut open, then this must be applied within one day.

If I use Flexim to secure the ridge tiles, then I no longer need to screw them down. Right?

It is important to assure proper anchoring of the roofing tiles and ridge tiles on the roof. This means that the ridge tiles must be secured to the ridge board using a stainless steel screw. Please note: the ridge tiles must not be affixed tightly against the ridge board; they must “hover” above the ridge board by at least 1 cm [0.4 inch].

Do you need a ridge board to attach the ridge tiles using Flexim?

A ridge board is a wooden board above the roof rafter or roof ridge for attaching the ridge tiles. In order to determine whether a ridge board is needed, you must first determine the application for which you will use Flexim.

There are two types of applications for Flexim.

  1. Roof repair: Flexim is used as a repair product for improving the bond between the ridge tile and roofing tile and for preventing (possible) leakage on and around the tiled roof.
    If you are going to use Flexim as a repair product, it is necessary to install a
    ridge board and then affix the ridge tile mechanically to this.
  2. Roof renovation or new construction: if you use Flexim for renovation or new construction, then we recommend that you install a ridge board if this is not present. The ridge tiles can then be mechanically attached to the ridge board for extra security. Make sure that the ridge tile is always attached to the ridge board using a stainless steel screw with a plastic washer.

Why do I need to wear gloves when working with Flexim?

5 latex gloves are supplied with every box of Flexim roofing mortar. Using the gloves is important because Flexim is a paste product that enhances the bond between the ridge tile and the roofing tile. By using gloves, your hands stay clean.

I want to secure the roofing tiles in the valley gutter. Can I do this with Flexim?

Flexim is ideal for supporting cut tiles in the valley gutter to prevent them from sagging. An additional advantage of securing the valley gutter in this way is that driving rain or snow can’t get under the tiles, preventing any leakage problems from occurring. We recommend inspecting this application once each year.

My flashing has sagged and ripped. How can I solve this?

Lead flashing is a strip of lead that is used as a watertight connection between parts of the building, e.g. around a chimney or roof window.

Using Flexim, lead can easily be repaired. Lift the lead up and wipe a small layer of Flexim under the lead. Then push the lead back into its position and tap it firmly into place.

How many metres can I do with a box of Flexim?

Flexim has developed a recommended use tool to approximate how much product (# of boxes) is needed to perform a particular application. The consumption for each 10-strip box of Flexim depends to a great degree on the application (roof ridge or hip, valley gutter or roof window), along with the type of roofing tile and ridge tile that are used. By default, you can presume that one box of Flexim with 10 strips can be used to affix approximately 3 to 5 linear metres of ridge tile on both sides!

Type of roofing tile and type of ridge tile
The so-called “concavity” in the tile can influence the amount of Flexim that is required. In other words, a hollow or deep roofing tile requires more material to ensure sufficient adhesion between the roofing tile and the ridge tile. Furthermore, a round ridge tile may require more Flexim to be used than a flat ridge tile.

When using Flexim on a roof ridge or hip, there may be a small difference in the amount of Flexim required. For example, slightly more Flexim might be needed on the roof hip because of the angle, whereas this is not the case at the ridge.

I have cement between the ridge tile and the roofing tile and now pieces are falling out here and there. Can I fill up the openings/gaps/seams with Flexim?

Yes! It is advisable to remove the ridge tiles first, remove the loose cement and make the surface dust-free. Flexim roofing mortar can then be used to re-affix the ridge tiles onto the underlying roofing tiles and the product then offers a guarantee.

However, in certain situations a cheaper solution might be to smear the cement with Flexim. After all, when repairing the ridge tiles, less material needs to be used than with completely new construction or renovation, and any possible leakage problems can be quickly addressed.

Roof repair

When performing repair activities, it is important to take a close look at the quality of the cement. If the cement is falling out in a number of places, then the loose cement must first be removed, and the subsurface must then be made free of dust and grease. After this, Flexim can be used as a filler material in order to perform a quick repair.

I spilled Flexim on a roofing tile during the work. What's the best way to clean this?

If the Flexim is still fresh, the tiles can be easily cleaned with a dry cloth or a cloth drenched in turpentine.

TIP: A small stain on or around the ridge tiles is often not visible from the ground and therefore need not always be a problem. If stains are nonetheless visible, then it is advisable to remove the stains immediately, of course. 

I spilled Flexim on a paving stone. What's the best way to clean this?

If the Flexim is still fresh, the paving stones can be easily cleaned with a dry cloth or a cloth drenched in turpentine.

If the Flexim is not removed from the stone immediately, the oil-based product may seep into the tile or stone, causing a stain. In extreme cases, a pressure washer (with steam) may provide a solution. However, we cannot guarantee this. Contacting a professional cleaning company may be advisable in order to ascertain how the stain can be removed from the tile or stone.

How many colours of Flexim are available?

Flexim is available in 7 colours.

  •  Black
  •  Red
  •  Grey
  •  Dark brown
  •  Light brown
  •  Blue
  •  Green

Can I paint over Flexim?

Yes, this can be done after a film/protection layer has formed on the product. Under normal weather conditions (10 to 25° C), a harder, protective layer forms after 2 to 3 days.

We recommend using alkyd paint. However, we provide no guarantee on the paint’s colourfastness or its application.

Can I also use Flexim if it's freezing outside?

Flexim can be used in temperatures down to -25°C! However, make sure that there is no snow on the uppermost row of tiles and that there is no ice inside the tile.

TIP: Cover up the uppermost row of tiles at night with a canvas, or place the tiles inside in a warm room. Put the tiles back on the uppermost row of tiles the next day and apply the Flexim roofing mortar immediately.

We also recommend storing the boxes of Flexim at room temperature (20°). Under colder weather conditions, the product can become somewhat tougher and stiffer to work with. Flexim is easier to use if the product is warmer.

Can I use Flexim when it's raining?

We do not recommend using Flexim when it is raining. Flexim is immediately water repellent, but if the roofing tile is wet or moist, this can affect the adhesion. If the ridge structure lies open and it starts to rain heavily, water may remain behind the Flexim product. This also causes a negative effect on the product and on the adhesion between the ridge tile and roofing tile.

Can you also use Flexim on old, used roofing tiles?

Yes, Flexim can be used on older roofing tiles and it adheres very well to ridge tiles. Make sure that the used tiles or ridge tiles are dry and free of dust and grease! Because of the age of used tiles, they can sometimes be dirty and we therefore recommend roughening up the inside of the old ridge tiles with a wire brush. This helps ensure an optimum bond between the Flexim roofing mortar and the roofing tile or ridge tile.

Can I use Flexim on my chimney top?

Using Flexim on the chimney top is not advisable and no guarantee is given for the result. Nor should Flexim roofing mortar be used to affix chimney caps.

Do the roofing tiles need to be wetted before Flexim is applied?

No, Flexim must be applied to a clean, dry roofing tile.

Which applications do you actually guarantee?

Flexim International B.V. guarantees Flexim roofing mortar as a sealing and adhesive material for a period of 10 years. This guarantee applies only if the Flexim roofing mortar is used as a sealing product for ridge tiles (roof ridges and hips) for new construction (both ceramic and concrete), and applied in accordance with our application instructions. Liability under the terms of this guarantee is limited at all times to the purchase price of the product.

Where can I purchase Flexim?

You can fill in your location on our Dealer page, and the closest supplier will be indicated. If there is no dealer in your region, please call or mail us! We may be able to help you further by finding another sales location in your area.

Discoloured Flexim after a period of time?

Flexim roofing mortar is a natural product based on linseed oil. After the passage of some time, the product can acquire a darker colour due to industrial contamination, attracting dust particles and UV.

However, Flexim can be easily painted over using alkyd paint.

TIP: It is important to cut off Flexim at a 90° angle. By complying with this recommendation, a so-called “shadow effect” will be created on your roof ridge. Should any discolouration then take place, it is likely to be virtually invisible.

Is Flexim hazardous to health?

On the basis of our experience and the information known to us, the product causes no damaging effects to health when used carefully and according to the instructions.

Flexim is not classified as hazardous in accordance with (EU) Regulation no. 453/2010 of the European Parliament and Counsel. It conforms with all requirements and limitations concerning the registration, evaluation and authorisation of chemical substances (REACH).

Our Flexim Safety Data Sheet will be provided upon request. We will be glad to send you this by mail.

What is a ridge tile?

A ridge roofing tile, or ridge tile, is a specially shaped roofing tile that covers the roof’s ridge or hip on a tiled roof. The most commonly used ridge tile is the “regular half-round ridge tile”. Ridge tiles are made in such a way that they overlap and hook into each other. With a nail hole in the ridge tile, it can be secured to the ridge with a roofing nail.

How can I keep birds from getting under my roofing tiles or ridge tiles?

Now and again, birds can make nests under the roof and other rodents try to get inside via the roof. Flexim can be used to close off seams, gaps or holes in the roof to prevent this from happening.

Do I have to use ventilation tiles?

On many roofs, there is natural ventilation. There are many gaps and seams in the roof through which air can pass. There is also natural ventilation with roofing tiles that don’t connect well (often old roofing tiles). In such cases, Flexim can be installed quite well without using ventilation tiles.

Roofs are often well insulated with both new construction and renovation projects, and insulation requires ventilation. We recommend using one ventilation tile for each 30 m² of roof surface, placing this on the second row of tiles beneath the ridge.

Does Flexim comply with the construction products guideline?

Flexim International B.V. confirms that its products comply fully with the requirements listed in the Construction Products Guideline 89/106/EEG. Pursuant to Article 66, paragraph one of Construction Regulation 305/2011/EU, products brought to market prior to 1 July 2013 are expected to comply with the Construction Regulation in accordance with EU Guideline 89/106/EEG.

Products from Flexim International B.V. are given CE markings on the basis of a European Community Declaration of Compliance.