Frequently Asked Questions

What type of tile is suitable for my roof?
The choice of the tile model is essentially aesthetic, but also functional, that is, interlocking models (Lusa, Marselha, etc.) are more efficient in providing water tightness at low inclines, as they have seals.
The natural overlapping models (Canudo, Escamas, etc.) require greater operating inclinations and/or more specific application techniques.
They are all aesthetically distinct and adaptable to more conservative or more contemporary architectures, depending on creativity.
What is the size of the lath work of a ceramic tile?
Each tile model has a different lath work measure.
The manufacturer should indicate the average/recommended lath work measure for each type of tile.
All catalogues have this information in the technical area.
What is the exact lath work suitable to my roof tile?
The exact lath work must not be indicated, but rather calculated/assessed on site.
Please check the corresponding Application Guide.
Can I use samples to mark the lath work on site?
No. It is recommended that the lath work is always marked/sampled with the tiles that will cover the roof.
How should lath work be calculated?
Lath work is nothing more than the average between the measure of a totally open fitting of a set of tiles and the corresponding measure with the fitting totally closed.
For more information, please consult the calculation methodology in the corresponding Application Guide.
What is the best material for lath work?
Laths can be made of metal, wood, PVC or prefabricated concrete.
The execution of mortar laths made in situ is not recommended.
Treated wood, due to its nobility and ease of application, is a recommended product.
What does the roof tile warranty cover?
Product and/or manufacturing defects provided that good construction practices are verified.
The EN 538, EN 539-1, EN 539-2, EN 1024 and EN1304 standards set the manufacturing conditions, resistance and acceptable variations in ceramic roof tiles.
I found two tiles on the same pallet with different sizes.
If the difference in size between them is less than +/-2% of the average value presented, then it cannot be considered a defect, but rather a nuance of the material (EN 1024).
I have two tiles of the same bundle, with different weights. Is this a defect?
If the difference in dimensions between them is less than +/-2% of the average value presented, then it cannot be considered a defect, but rather a nuance of the material (EN 1024).
The tiles on my roof do not have exactly the same shade as the accessories. Can this be considered a defect?
If the difference in colour between the tiles is not too great, this cannot be considered a defect, but rather a nuance of the material (EN 1024).
Can I return the tiles left over from my work?
Yes, but always within the conditions of the UM commercial policy.
It is advisable to read the current price list.
What is a ventilated roof?
A ventilated roof is a roof where the air inside the roof (air gap/ventilation) can circulate and evacuate naturally, being regenerated at every moment.
For more information, do some research about "thermal draught principle".
What are the ventilation components used for?
To help the correct application and ensure the intake and evacuation of air into the roof
What are mechanical fixing accessories?
These are pieces designed and conceived for fixing ceramic tiles.
They allow the efficient fixation, water tightness and ventilation of each single point on the roof.
Do I have to fixate all roof tiles?
No. Depending on the area, protection status of the building and inclination of the slopes, you may only need to fix singular points (ridges, eaves, emerging walls, etc.) or all tiles.
We recommend you to read the corresponding Application Guide carefully.
UM tiles are very difficult to drill. What can I do?
It is recommended to always try to pierce in the areas foreseen by the moulds, that is, in the pre-perforations.
Even so, and in case there are no pre-holes, the following principles are recommended:
1. Use suitable drills (diamond) without the action of the hammer drill;
2. Wet the pieces well with water, until saturation is reached (leave in water for 24 hours);
3. Drill with constant speed and strength;
4. Wet the drill/ceramic contact area regularly during the process in order to avoid overheating.
What are the regulations for the execution of roofs in Portugal?
Unfortunately there are no regulations for the execution of ceramic roofing in PT.
It is recommended to read the existing Application Guides and Good Practice Manuals carefully – E.g.: "Guia para Projeto e Aplicação de Telhas Cerâmicas - APICER 2019"
How to identify the minimum slope of a roof?
Check the respective Application Guide and analyse the following parameters:
- Measure the longest slope of the roof
- Identify the geographical area according to the map
- Identify the building's protection status
Subsequently, you only need to adjust each one of them in the corresponding table to obtain the value.
My house is on the border of Zone III and Zone II. Which one should I consider?
You should always be conservative, that is consider the Zone of greatest influence of meteorological/geographical agents. - Zone III
My house is neither on top of a hill, nor at the bottom of a valley. What is the protection situation?
The protection status will be "Normal".
I cannot comply with the minimum inclination. Can I use roof tiles?
Yes, but you should consider the option of using complementary means to reinforce the water tightness of the roof. This could be sub-tiles, membranes, etc.
What is the proper under-tile?
Breathable and waterproof membranes, due to their lightness, resistance and flexibility, are the recommended option. They are also usually the most economical options.
When fixing the supporting lath over the membrane, I will perforate it. Is this not a fragile point, susceptible to infiltrations?
Nowadays, the sheets and membranes, depending on their quality, are manufactured with polymers that adjust to the breaking points.
Even so, if a primer is applied and a roll of membrane is placed over it, the roofing fabric will be perforated at a high point, which does not constitute a risk of infiltration.
There are also insulating tapes on the market for waterproofing the underside of laths and counter-laths, thus ensuring greater water tightness.
What is a counter-buckling?
It consists of placing a longitudinal lath on the slope, that is, watertight, perpendicular to the ridge and corner lines.
What is the proper distance between the laths of the counter-buckling?
The distance depends on the structural conditions and on the dimension/strength of the lath. However, 0.5m can be considered the normal distance for our products.
My roof tiles show superficial greening. Is any action recommended?
You can always carry out "non-evasive" maintenance cleaning using recommended products.
Consult the Quality Department.
What is the "advance" measure of the cymatium that the tile can leave at the eave?
Never exceed 50% of the length of the pieces and always adapt the fixings.
For further information, please contact the Technical Department.
Am I forced to install ventilation tiles?
No, but it is strongly recommended.
3 to 4 units should be applied per every 10m2, on the perimeter and intermediate roof rows, and always in quincunx.
Consult the Application Guide.
How should my roof be maintained?
A roof applied using good construction practices does not require periodic maintenance.
Roof maintenance is essentially visual.
It is recommended to check intersection points and water drainage before the rainy season to avoid clogging caused by rubbish, leaves, etc.
Am I required to put clamps on all UM Canudo tiles?
Normally yes.
Depending on the application conditions, the clamp can be avoided on Bicas tiles.
If the roof tiles are all bolted down, clamps are not necessary.