In 2010, Finnfoam introduced a new foundation mold that facilitates construction. The solution utilizes the excellent strength properties of Finnfoam. In addition, the structural solution is cost-effective and easy to construct.
Today, frost insulation is often installed under the foundation. In passive and zero-energy houses, the frost insulation should always be installed under the foundation to ensure that thermal bridging is eliminated effectively. The thermal insulation of cold buildings and open shelters should also be installed under the foundation, ensuring a sufficient width. The recommended width is 2–5 meters.
The installation of insulation no longer has to be a separate stage, as it can also be used to create a foundation mold. The Finnfoam foundation mold allows you to produce foundations quickly and easily. Finnfoam is extremely strong and durable under the foundation.
View an animation of the foundation mold...
The foundation mold panels have been specially cut to form, and they have ready-made folding points for the upright sections of the mold. The upright sections are separated from the panel at the construction site. The upright walls of the mold are slotted into the groove on the panel, thus creating a sturdy foundation mold. The upright walls are always attached to the bottom section such that they bind two bottom panels to each other.
The mold is reinforced at the construction site. For horizontal reinforcement, a chainsaw is used to cut installation slots into the upright walls of the mold for the widthwise bars spaced a little over one meter from each other. The lengthwise bars are laid on top of the widthwise reinforcement. The widthwise bars also function as support for the upright walls. The widthwise bars should be bent into a U shape such that the distance between the points is 740 mm. Concrete is poured into the mold in the regular manner. The U-shaped bars may also be made from 5 mm thick stainless steel if the design so requires.
The foundation mold is kept in stock in two different sizes: 600 x 200 mm and 460 x 580 mm (internal dimensions). Each mold is made from 70 mm thick F-400 strength class Finnfoam insulation, which means that the insulation can withstand a continued load of approximately 18 metric tons/m2. The solution can be used to simultaneously create a well-insulated foundation and a casting mold where the reinforcement bars for the sides also provide support for the lengthwise reinforcement. As a waterproof and impermeable material, Finnfoam also prevents capillary moisture from transferring from the ground to the footing.
Foundation mold 600 x 200 mm
1. Break off the panel pieces by folding at the intersection.
2. Slot the upright wall of the mold into the groove in the bottom panel. Attach the pieces to each other in an overlapping manner such that each upright wall connects two bottom panels.
3. Cut slots into the upright walls for the horizontal reinforcement of the foundation. The widthwise reinforcing bars are bent at the ends, which allows them to support the mold as well. The distance between the points must be 740 mm, which is the width of the mold.
4. Miter the bottom panels of the mold placed into the corners from the middle, but do not cut the side sections. The bottom panel cannot be turned over, so use the pieces left over on the next corner.
5. Cut the side sections to the correct length and connect them with a butt joint. Bend the ends of the lengthwise bars into the slots cut into the mold. Bind the reinforcement bars to each other to ensure solid corners.
6. Insert the reinforcement bars with the bent ends into the slots in the panels and attach the lengthwise bars on top of them.
7. Insert the dowel-bar reinforcement for the wall structure into the wet concrete.
Foundation mold 460 x 580 mm
1. Place down the foundation mold such that each upright wall connects two bottom panels to each other.
2. The foundation mold is reinforced according to the structural plans of the site.
3. Create the external supports for the foundation mold using 50 x 100 lumber. If the casting height is 400 mm or less, the walls can be supported with a single horizontal lumber support of 50 x 100 mm, which is installed at an approximate height of 200 mm. Correspondingly, casting heights of 400–600 mm will require 2 horizontal supports of 50 x 100 mm. The horizontal supports are placed evenly on the middle of the mold and the top edge. Two 50 x 100 mm studs are placed at little over one-meter intervals.
4. In between two studs, push a reinforcement bar through the insulation vertically in the middle and through the opposite vertical insulation and the two opposing 50 x 100 mm pieces of lumber. Finally, use mold clamps to lock the ends of the reinforcement bar in place. This will provide secure support for the Finnfoam foundation mold.
5. Pour the concrete in the regular manner.