Thermal insulation on the outside of an eco-sustainable wooden house with the AISTERM system.

System description

A wooden house is a type of construction that can compete without problems with traditional constructions (brick, concrete,…). Thanks to the warmth, comfort and versatility of this type of material, more and more families are choosing this type of construction.

Among its advantages is that it is a sustainable construction, as wood regulates the interior temperature and controls the humidity of the house, making the use of air conditioning elements (heating and air conditioning) less necessary.

Another of its advantages is that it is an ecological construction that is quick to build, clean, consumes very little water and little energy, as well as being a renewable resource.

All of this, together with very competitive construction prices and a high degree of versatility in adapting to any house design, makes this type of housing increasingly attractive.

In addition, these advantages can be complemented and improved with external thermal insulation systems (SATE) that are totally suitable for this type of construction, thus obtaining an eco-sustainable home. This type of solution has been proposed and subsequently implemented in the house described in this article.

Reason for the intervention

Application of the SATE system in eco-sustainable housing in the Sierra de Collserola.

Challenges and constraints

“The main challenge we faced when carrying out this application is the type of support characteristic of this type of construction (wood).
“The Exterior Thermal Insulation System supplied by Molins must comply with the basic document, DB HE on energy saving, established in the CTE (Technical Building Code).
“The new cladding system must be environmentally friendly and continue with the construction philosophy chosen by the property.

Molins Solution

Application of the AISTERM SYSTEM on all the façades of the house:

“Laying of extruded polystyrene (XPS) insulation panels and fastening of these panels using specific wood screws.
“Application of PROPAM® AISTERM adhesive and reinforcement mortar and PROPAM® AISTERM MALLA FIBRA DE VIDRIO 160 mesh on all the facades of the house.
“Finishing of the AISTERM SYSTEM with REVAT® PLAS acrylic mortar after priming with REVAT® FILM.

Execution

“Application of the adhesion primer PROPAM® FIX to improve adhesion to the surface of the wooden substrate and prevent the absorption of the water from the mixing of the adhesive mortar by the wood.
“2. Lay the XPS insulation boards with PROPAM® AISTERM adhesive mortar on the prepared substrate, using a toothed trowel to comb the mortar over the entire back of the board.
The boards are laid from the bottom upwards, starting from one edge of the house, butt-jointed, butting up against each other and with no gaps.

“3. 24 hours after laying the panels with PROPAM® AISTERM, mechanically anchor them with PROPAM® AISTERM WOOD SUPPORT PLUGS, which are special for fixing panels to a wooden substrate, at a rate of 6 plugs per m2.

“Protection of the slabs by spreading a layer of PROPAM® AISTERM mortar and placing the PROPAM® AISTERM MALLA FIBRA DE VIDRIO 160 mesh over the fresh mortar layer, with 10 cm overlaps between consecutive meshes.
After 24 hours, apply a second coat of PROPAM® AISTERM and regularise the surface.

” 5. Application of a coat of REVAT® FILM acrylic facade coating, once the PROPAM® AISTERM protective mortar has dried and hardened, as a base coat and to homogenise the absorption of the substrate.
Application of REVAT® PLAS acrylic mortar after 24 hours, as a finish.

Technical note

The fixing of an External Thermal Insulation System (EIFS) is achieved by the adhesive mortar and the mechanical fixings.
The mortar binds the ETICS to the base material and transfers thermal loads and stresses (expansion/contraction) and the mechanical fasteners work with the mortar to contrast horizontal stresses and loads (wind suction/depression). It is very important to know how to choose the type of dowel required depending on the substrate on which the system is to be fixed.
In the case of wooden supports, dowels consisting of a plastic washer and a metal screw must be used to screw the insulation board (EPS, XPS, etc.) onto the support.