ICF Filter House/Pavilion Progress!

For a chronological listing of our building projects with ICF (or insulated concrete forms), be sure to look through the ICF Building Index.

We are becoming quite competent building with ICF (insulated concrete forms)! The ICF filter house/pavilion has taken the skills learned so far to a new level – we are applying a stucco finish. Actually, we thought it would be good to practice on something small before we complete the final stages of building the house! So, the octagonal filter house is the ideal project.

If you remember, last week we poured the concrete to fill the ICF walls. This week has been spent on finishing the inside and outside stucco. We decided on stucco because we like the Tuscan style, it gives a nice finished look and protects the styrofoam of the ICF. Rather than traditional stucco, we decided to use a synthetic stucco which is not only a fraction of the thickness of the traditional version but is also stronger, lasts longer and adds insulation value.

EIFS (exterior insulation finishing system), is applied in three steps over the ICF blocks. The first coat is a polymer modified cement. It is a mix of cement, fine sand and a polymer which adds strength and prevents cracking. It is applied in a thin 1/8 inch coat over the styrofoam blocks using a trowel.

Working in a small area, a fiberglass mesh which is bright yellow is embedded in the wet cement. The trowel is used to press and smooth the concrete over the mesh covering it.

The mesh is 3 feet wide and one person holds the roll of mesh to the wall while another presses it into the cement.

After the fiberglass mesh is completely covered with the cement, a wet sponge trowel is used to further smooth the cement coating. This prepares the surface for a smooth finish coat.

Since the walls are 8 ft tall and the mesh is 3 ft wide, it is taking two passes of the full width and one with a cut section.

To cut the mesh, it is laid on a board and cut with a utility knife and straight edge at the desired width.

The final step to complete the stucco is a waterproof finish coat which will be applied after the concrete stairs are finished. There have been a lot of tired and sore arms, necks and backs around here this week! On the bright side, a lot has gotten done, everyone got a great workout physically and we did not have to pay for gym memberships!

So, for now, you can see the stairs are being formed on the right side of the picture below and the filter house/pavilion is gray except for a Spanish tile sundial that was cemented to the wall – can’t wait until it is a pale yellow!