Exterior insulation system on OSB board

Descripción sistema

Location
Chiloeches (Guadalajara)
Distributor
Proyecsa Plasters
Applicator
Abdel Monsuri
Type of work
Facade cladding and insulation works
Owner
Owner of hotel restaurant
La Posada de Consuelito

Intervention date
Year 2021
Molins Products
COMPLETE AISTERM SYSTEM ON WOOD
PROPAM® GRIP +
EPS SHEET
SPECIAL PLUG ON WOOD
PROPAM® AISTERM GLASS FIBRE MESH 160
PROPAM® AISTERM
REVAT® FILM
REVAT® PLAS

More and more houses are being built with facades made of natural materials for sustainable construction.
OSB (Oriented Strand Board) is a board made of large wood chips pressed and bonded with resins. Each of its layers is oriented perpendicular to the previous layer, which gives it a homogeneous behaviour when subjected to expansion or forces in different directions. In addition to its great strength, OSB is a great thermal and acoustic insulator, properties typical of wood, which makes it a very suitable product for façade and roofing projects in sustainable architecture. It is a relatively inexpensive material and its installation contributes considerably to the reduction of execution times.

Reason for the intervention

This is a newly built hotel in OSB board where it is desired to cover all the walls and walls facing the exterior in a way that waterproofs and protects the board from external agents.

Challenges and constraints

The challenge is to install a system that adapts perfectly to the dilatations of the substrate under consideration, which adds to the complexity of the work due to the unique and architecturally beautiful galleries and dormers.

Molins Solution

The solution proposed by Molins is the installation of a SATE system because we understand it to be the most suitable for the protection and conservation of a support derived from wood. This is achieved through the use of a protective primer and at the same time a bonding bridge, the product PROPAM® GRIP + meets these needs. Subsequently, a SATE PROPAM® AISTERM CONFORT system evaluated according to ETE 09/ 0005 with a variant in the co-location of fixings with screw plugs on wood.

Execution

The cladding work was carried out by Abdel Monsuri, who has extensive experience in SATE façade finishes.
The execution was carried out as follows:
“1. PROPAM® GRIP + was applied to the entire surface of the clean and dust-free board. This primer acts as a moisture protector and establishes an ideal bonding bridge for the system to be installed, from approximately one hour after drying, it is important not to exceed 24 hours from its application to the installation of the boards.

“2. Once the bonding bridge has been applied, the EPS insulation boards are installed. In this case, the minimum thickness of the sheet was used (3 cm) as energy efficiency was already calculated and solved in the façade by means of rock wool between panels.

Molins’ recommendations are always based on the execution of a double gluing or a good solidification and flattening of the sheet, achieving 100% contact with the substrate as far as possible. In no case, this contact will be less than 60% of staining of the board as indicated in the ETE 09/ 0005 evaluation.

“After at least 24 hours, the boards were screwed together with special wood dowels at a rate of 8 dowels/m2.

“4. Both starting profiles and corner profiles were installed, which were very useful for the number of corners on the site.

” 5. The system consists of a flexible waterproofing mortar, PROPAM® AISTERM, to which an alkali-resistant glass fibre mesh, PROPAM® AISTERM GLASS FIBRE MESH 160, is incorporated in half its thickness. This process was carried out in two coats in a total thickness of 3-5 mm.

“Finally, REVAT® FILM BLANCO was applied as primer and REVAT® PLAS BLANCO as decorative finish for high protection of the system.

Technical note

These works have been carried out taking into account the basic requirements of the Technical Building Code (CTE).
SISTEMA PROPAM® AISTERM, in any of its finishes, is intended for use as thermal insulation on the outside of building walls. The walls can be masonry (brick, block), concrete (made in situ or based on prefabricated panels), or especially in wood derivatives with anchors prepared for this purpose. The system is designed to provide the wall on which it is installed with a very satisfactory and durable thermal insulation.

It is composed of non-load-bearing elements. It does not contribute directly to the stability of the wall on which it is installed, but it contributes very favourably to its durability by protecting it against natural agents, thus providing extra protection to the structure.

It is totally suitable for the situation (by the sea), environment (saline) and adverse weather conditions foreseen for its installation, as its durability has been tested using the hygrometric cycles indicated in the EAD 040083-00-0404 (External thermal insulation systems), which have determined that it shows a fully satisfactory behaviour, that is, during the heat-rain and heat-cold cycles, without any of the following defects:

– Pockeying or spalling of finishes and flaking of the cladding.
– Failure or cracking associated with joints between edges of insulation or installed profiles.
– Cracking of the cladding allowing water to penetrate the insulation.

On the other hand, the water absorption results of both the base layer samples and the System with its finish are less than 0.5 kg/m2 after 24 hours, so the System is considered to be resistant to freeze/thaw cycles.

The base facing must have sufficient bearing capacity to resist the combined loads of: self-weight, weight contributed by the SATE and the wind loads transmitted through it.
These elements used in general are indicated in the following rendering.