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Comparison between waterproofing systems

Thin bed waterproofing


The substantial advantage of the thin bed waterproofing system is to ensure the same seal as the traditional waterproofing system with PVC sheet, but with a significant underfloor space saving: in fact, once the screed has been made and the waterproofing sheet laid you can directly proceed with the tiling of the floor.

  1. Screed
  2. First layer of tile glue or Deflow MS
  3. Waterproofing tech fabric or Deflow Tech
  4. Second layer of tile glue or Deflow MS

PVC sheet waterproofing


The traditional waterproofing system with PVC sheet is still widely used, especially for balconies, terraces and cellars isolation.
Compared to the most recent thin bed waterproofing, this technique requires an additional layer of screed of at least 40 mm to fix the sheet and, furthermore the walls waterproofing of the walls is not possible.

  1. Screed
  2. PVC waterproofing sheet
  3. Ballast screed (40mm at least)
  4. Tile glue or Deflow MS

Important warning

Event 1
The standard package content is enough
The base package of the TEA products series contains the ready to be installed product only on floors lain on earthwork where any infiltrations can be absorbed by the underlying ground.
Refer to Level 0 of the waterproofing safety levels listed on the next section.

Event 2
A waterproof seal is required
To install TEA products on slabs is required a waterproof seal that prevents water leakage to the underlying floors.

Such waterproofing can be obtained using the accessories offered in this page, or using other third party system products. In this case, before proceeding with the installation, verify the compatibility of the products used.
Refer to Level 1, 2 and 3 of the waterproofing safety levels listed on the next section.

The technical details and recommendations contained in this catalogue are based on our knowledge and experience, however all the information must be consider as general guidelines only. Anyone who intends to install the OMP TEA products must ensure that they are suitable for the correct application. In every case the installer is fully responsible for the installation of the products and for any resulting consequence deriving from it’s work.

Waterproofing security levels

Suitable for installations with flooring on embankment only

The installation of TEA’s drains on slab (at elevated floors), without any proper waterproofing, may cause water infiltrations to below floors as well as considerable damages.
This eventuality, if the product is laid without waterproofing, can not be attributed to a bad functioning of the product.

Deflow MS, smeared adequately over the entire surface, will ensure good waterproofing as long as the coating work is performed to the highest standard.

A good tiler’s intervention is necessary.

The tile glue (available through retailers of building materials) is needed for anchoring the Deflow Tech sheet to the slab.

The Deflow Seal elastoplastic tape should be used to accurately seal all joints and patches.

The work in sealing joints and patches should be accurate. Any omissions may create possible infiltration entries.

Use the Deflow MS case to anchor the Deflow Tech sheet and to seal all joints and patches: seal is doubly secured.

Strongly recommended for frequently used showers: hotels, spas, gyms, etc…

The Deflow MS adhesive case can also be used for pavement laying.

In this way, Deflow MS will fit in the spaces between one tile and the other sealing the joints perfectly: very useful for preserving the underlying masses.

Products for waterproofing

Deflow Tech

Deflow Tech is a waterproof tech fabric composed of two outer layers of polypropylene TNT, which guarantee glue gripping, and an inner membrane of waterproof polyethylene.
It is resistant to chemical stress that normally acts on ceramic coating; moreover, it does not deteriorate; it is non-biodegradable and it has high elasticity. Deflow Tech finally showed exceptional resistance to salt solutions in water dispersion, to acid and alkaline substances, to many organic solvents, to alcohols and to oils.

The Deflow Tech sheet is widely used as a protection product against humidity and noxious substances on floor substrates and coatings of bathrooms, showers and swimming pool perimeters.
The studs on which the waterproof sheet is intended to be placed must basically be planar, stable and clean; before applying Deflow Tech, any residue that could compromise adhesion must otherwise be removed from the surface. Polyethylene is a perishable material on UV rays; so, it is important to avoid long exposure to sunlight during storage.
It is advisable to request for a specific verification of product performance, in cases where particular strains on concentration, temperature and time exposure are foreseen.

5 meters roll
art. 979.141.0
(1500mm × 5m)

20 meters roll
art. 979.142.0
(1500mm × 20m)

angle component
art. 979.300.0

edge component
art. 979.500.0

Deflow MS

Fast polymerization waterproof elastic, adhesive, spreadable, single component, MS polymer-based mastic.
Deflow MS is a specific product for waterproofing horizontal and vertical surfaces in permanent elasticity and excellent grip, which polymerizes thanks to the environment’s humidity.
Compared to other waterproof mortar manufacturers, Deflow MS, other than being a seal stop case, is also a good and strong adhesive.
Using Deflow MS to anchor the Deflow Tech sheet doubles the security level of the waterproofing package.
Furthermore, Deflow MS can also be used as glue for tile coatings.

5 kg bucket
art. 979.850.0

overall theoretical yield
for waterproofing
1,5 kg × 1 mq

for Deflow Tech fixing
0,9 kg × 1 mq

Deflow Seal

In the case of Deflow Tech sheet placement, a standard tile cement glue needs to be used to ensure a seal stop of the sheet, it is essential to seal all the junctions and joints using a Deflow Seal elastoplastic double-sided tape.
It is a double-sided tape composed of butyl rubber compound and is characterized by immediate adhesiveness and permanent bond strength.
It is recommended to carry out sealing process with great care to ensure safe impermeability.
This alternative offers cost savings in terms of materials, but waterproofing without a specific Deflow MS glue increases the complexity of work and increments the costs of labour.

tape width 15 mm
art. 979.810.0

15 mt roll

tape width 50 mm
art. 979.811.0

15 mt roll

Thin bed waterproofing instructions


After placing the drain set for floor mounted shower (follow the instructions in the package), and having correctly levelled the screed bottom with appropriate slopes (min 1%), make sure that the support is free of defects that could compromise the sheet’s adhesion by removing any residue from the surface.


It is necessary to cut and model Deflow Tech plates and sheet strips fitting them to the area to be applied on before adding the mastic.

It is not necessary to be very precise in cutting the sheet: any defects will be covered by the joints.


Secure the waterproofing shaped sheet, included in TEA standard package, by spreading the sealing mastic Deflow MS (or similar products) between the sheet and the screed with a trowel.


Allow the sheet to perfectly cling to the substrate making sure that air pockets are not formed.


Spread the Deflow MS adhesive mastic also on the sheet surface.


Uniformly spread the Deflow MS mastic on the entire surface of the shower floor.


The laying of the pre-emptively cut Deflow Tech sheet can be done once the glue layer has been stretched.


Push the Deflow Tech sheet using the scraper’s smooth side in an angled direction relative to the same sheet exerting a certain pressure so as to avoid the formation of air pockets.


Vertical flaps need to be used when the Deflow Tech waterproof sheet has been carefully placed on the horizontal surface to achieve an ideal seal stop.

Edges and corners can be easily flapped using the available moulded pieces.


Dispose once again the Deflow MS waterproof mastic in the corners of the bathroom and then paste the appropriate moulded pieces.


Do the same for all the angles and corners of the shower floor.

This type of process becomes critical when it comes to installing a Deflow system on slabs.


Finally, proceed with the drafting of the Deflow Tech waterproof sheet along all the edges like the ones in the angles.

Make sure that in the junction points, the Deflow Tech sheets are overlapped for at least 5 cm.


The shower space is now waterproofed and ready to be tiled. For the laying of the tiles, apply the glue directly on the Deflow Tech sheet.

The mastic is also a good glue for the tiles. Using Deflow MS for the laying of tiles increases the level of security of the entire waterproof system. Moreover, the tiling can be done immediately “wet on wet” without waiting for the hardening of the layer below.


With the Deflow system it is also possible to waterproof vertical walls in order to install, for example, sauna shower and to avoid any type of moisture infiltration from adjacent rooms.

The terms and instructions for installation on vertical walls are similar to those described for floor laying.

Video instructions

art. 953 Nanoflow

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