475 has been a vocal and outspoken proponent of foam-free building. But as we’ve said, we also know that in the push toward foam-free construction, targeted and limited applications of foam still make sense.
We always look for products that solve issues building professionals face when optimizing the building envelope. Not only does a high performance building need a continuous air barrier – it also needs an uninterrupted layer of insulation. Load-bearing connections in or through exterior insulation materials can be particularly challenging. Supporting windows and doors is one of the most common problem areas, but other trouble spots include balcony connections, mounting shades at lights, and heavy rainscreens. These interruptions (aka thermal bridges) lead to a number of issues, including excessive heat losses, reduction in overall insulation effectiveness, and condensation formation inside at cold surfaces.
Linear thermal bridges
When installing windows or doors, it has generally been tricky to mount the window out in the middle of the insulation on the exterior of CMU buildings. The conventional alternative, namely setting the window directly on the block wall, is not ideal thermally. With CF100 (under sills) and or CF200 (for screwed connections), the architect and contractor now can move the window out into the insulation and thereby dramatically improve the installed insulation performance. As defined by the Passive House Institute, linear thermal bridges can be disregarded in energy modelling if they are below Ψ ≤ 0.0058 (BTU/hr.ft.°F) (or <0.01 W/(mK)). With CompaCFoam, thermal performance can be improved by as much as a factor of ten. Gone are the days when highly thermally conductive brackets or screws used to connect windows and doors create inefficient and potentially damaging thermal bridges.
When mounting rainscreens, shades, tie back balconies, railings and any other way that screws go through the insulation layer, CF100 can help as blocking to space the brackets from the wall and insulate them.
However, if there is a steel to steel connection, CF200 or higher can be used, and screws can be offset. So the CF200 is secured to the metal structure behind and the item to be mounted is secured into the CF200. This completely eliminates the metal to metal conductivity and as a result drastically improves the installed values.
High Load bearing applications
Under columns at foundations and other elements where structrual loads are being transferred to CompaCFoam, the higher density CF300 and CF400 can be used. Do make sure to properly fireproof such elements or the building itself.
CompaCFoam is very easy to tool, and practically can be worked in similar way that wood can and with the same tools. However when cutting, routing CompaCFoam it is important to use the right blades – large tooth spacing recommended, but please contact us when in doubt (and do not it does create a distinct odor). Other prefabrication methods that are available are milling for window profiles, or hot-wire cutting – which is also possible in multi-axis.