January 16, 2014

The GUTEX Wood Fiber Board Primer: vapor open continuous insulation & WRB

wood chemical compositionGUTEX wood fiber insulation boards are made with post-industrial recycled wood chips and shavings of spruce and pine. The boards are produced by using an innovative dry method, which is much less energy intensive than the conventional wet method and minimizes additions of binders and hydrophobic wax.  The result is the ultimate natural insulation material – insulation with a wood content of 94-96% that has superb properties for interior and exterior applications. Its uses include roof-underlayments/continuous insulation & WRB for rainscreens, EIFS systems, interior insulation/plaster-boards and insulation boards for floors/roofs.

This post goes into detail about the various benefits of the dry material production and it’s many beneficial properties (insulation, decremental delay, IAQ, soundproofing, fire resistance, end of life uses, environmental). The boards can be used to insulate and weather-in your assemblies, while at the same time increasing drying potential and reducing environmental impacts – areas where exterior foam fails.

In one step – weathertight and continuous insulation

tongue and groove GUTEX wood fiber boardsThe biggest benefit of GUTEX’s ULTRATHERM and MULTITHERM boards is that an enclosure can now keep the elements out in one fast and simple step. The boards are applied at the exterior, and tongue and groove (T&G) edges makes installation very fast. Because you do not need to line the vertical edges of the boards up with the studs/joists below, you minimize cutting, reduce waste and maximize application speed. The T&Gs also assure that the boards are waterproof and wind-tight right away. The building is now protected from the elements during the interior construction phase. The final cladding/roofing should be added within three months.

Taping valleys, wood fiber board joints with TESCON VANA and Primer RPThere are a few remaining details such as valleys, outside corners, dormers, chimneys or windows that need to be additionally waterproofed with tape connections. Simply prime these areas with TESCON Primer RP, and use TESCON VANA 150 to make these connections waterproof and windtight.

Insulation that is vapor open and weather resistant

GUTEX wood fiber boards from dry production are very vapor open Vapor open wood fiber board GUTEX– with 44 perm/in to make sure that moisture in your walls can dry out if unforeseen humidity or moisture enters the assembly. They provide  a high drying capability to insulated enclosures – not possible with foam boards – keeping them dry and allowing drying with the same material.

Acoustic insulation and thermal lag

Densities range from 8.75lbs/CF (MULTITHERM) to 12.5lbs/CF, giving the boards ideal acoustic properties. Sound transmission is further reduced by the tight T&G joints. These properties also make it an effective buffer against impact sound and can work in roofs, walls and floors.

Time lag and decrement factor with 180mm GUTEXThe high density, combined with high specific heat capacity, results in a material that heats up slowly and has very good thermal diffusivity. The boards can delay temperature rise by 10 or more hours (in combination with dense-pack insulation). This thermal delay will keep the house cool during hot days, but comfortable at night. In contrast, low density materials like foam, mineral wool or fiberglass will heat up rapidly and cannot offer this benefit.

Dry production – maximum wood content, minimum environmental impact

The benefits of GUTEX’s innovative dry production are twofold:  wood content in the boards is increased, and the energy required to produce them is reduced. The conventional wet method involves a larger amount of additives (~3% white glue, 2% paraffin for hydrophobic properties, 5% latex for strength), resulting in a wood content of ~90%. More water is also required, which then has to be dried out with an air-dryer – a process that is 40% more energy intensive.  Finally, the maximum thickness of boards with the wet method is only 1″ (25mm), so thicker boards must be laminated. In comparison, the dry method can produce monolithic wood boards up to 9.5″ thick.

dry process GUTEX productionIn the dry method, the chips are defibrated and sprayed with paraffin in warm air – this dries the fibers, which are then sprayed with 4% PU resin solution and spread out over a board former. These materials are then placed in a special curing unit in which the resin cures through its exposure to a mixture of air and water vapor. Tongue and grooves are then milled and the boards are packaged. The dust of milling is reused in the production process.


Environmental benefits – carbon sink/FSC certified

GUTEX wood chips and shavings

GUTEX is made from renewable natural resources and harvested from FSC certified forestry. The raw materials are by-products (post-industrial) from other timber manufacturing processes. The untreated shavings and chips used in the production come from local sawmills. The boards themselves can be reused at the end of life – and are biodegradable or can be used as a fuel source.

wood chemical composition GUTEXAs wood grows it absorbs CO2 from the atmosphere and locks it in place. By turning these manufacturing by-products (wood scraps) into energy-saving insulation rather than fuel, less carbon dioxide is released into the atmosphere from both heating/cooling savings and carbon sequestration.

Application – weathered in, in one simple step

GUTEX MULTITHERM rainscreen wallMULTITHERM boards can be stacked against the structural wall studs. The joints do not need to line up with the studs behind. Vertical joints do need to be offset minimum 20″, and maximum spacing of the studs behind 1-9/16″ thick boards is 24.5″ on center. The boards can also be mounted without sheathing, saving materials and time. However, the boards do not provide lateral/structural support for the structure – this must be accomplished with cross bracing or other engineered solutions. Immediately after boards have been placed on the wall, vertical battens should be installed to secure the boards to the structure. The battens will be later used as supports for the rainscreen cladding.

ULTRATHERM boards are laid on top of roof rafters.  Again there is no need to line up seams with the supporting structure and no need for structural sheathing below these insulation boards – as long as the on center distance of the structure is less than 43″ and boards are offset at least a rafter bay. After the ULTRATHERM is applied, vertical and/or horizontal sheathing (depending on roof type) is placed on top and secured into the structure below. Additionally all roof penetrations must be gasketed or taped with appropriate solutions.  Please follow all other recommendations in the specific product application guides.

ULTRATHERM roof application

3D Sketch of Typical Gabled Roof Construction

When looking for sustainable high-performance continuous insulation solutions, 475 and GUTEX have the answers – with boards now in stock.   Contact us for more information.

, , , ,

Tweet about this on TwitterShare on FacebookShare on LinkedInPin on PinterestEmail to someone
No comments yet.

Leave a Reply