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Foundation Lining - Footing Sides EPS

Star The sides of the footing trenches are lined with polystyrene with it thicker towards the top.

Line footing trench with pre-made EPS assemblies

Line outside of footing trench

You may well need to trim the bottom edge of the EPS assembly to make sure it does not come up higher than the top of the outer upper Form-A-Drain.

Trim Eps Outer Bottom 

It is also good to round off the edge to help it sit better against the polyethylene sheet.

Bevel Trim Outer Eps Bottom 

You can make sure the EPS assembly is not sitting too high by using a bubble level off the top of the outer upper Form-A-Drain.

Eps Upper Right Height Level 

When fitting the EPS assembly, make sure there is something like 2" of slack in the polyethylene sheet so it is not accidentally stretched.  Note that the polyethylene sheet folding does not need to be folded neatly as it will all be flattened behind the EPS.

Slack In Membrain Before Eps Vertical 

Use the pre-made wood clamps at the top to attach to the outer upper Form-A-Drain.

Wood Clamps Eps Outer Form-A-Drain 

Attaching only at the top is ok because the horizontal EPS at the bottom of the trench will hold the bottom of the vertical EPS.

Initially just get the 8' lengths of EPS assemblies in place.  Don't initially worry about the corner pieces.

Site First Membrane With Some Eps

Squirt foam gap filler into the join between the edges of the EPS assemblies to hold everything together.  It does not need to be a water-tight join.

Line inside of footing trench

It should stick up 2" above the top of the upper inner Form-a-drain which means it will be level with the top of the first 2" EPS that will go over the slab area.  Use foam gap filler on the edges between the sheets.

Add bracing lumber with pads

The bracing wood spacers are pieces of scrap lumber cut to a length of 3'3".  With the 2 times 3.5" of the EPS+wood pads and an additional 2" of EPS, that makes a width of 4'.  At the bottom of the trench the designed width between EPS is 4'1", but half way up the trench it is ok to have half an inch of inwards bulge at each side which reduces the width to 4'.  The extra 2" pad of EPS is used at this stage because it takes the place of the extra 2" EPS piece on the inside of the trench which will be glued on later after the EPS at the bottom of the trench.

The EPS may be a bit curved and the trench may have contracted slightly so I find it useful to use a home-made hydraulic spreader tool to make it easier to fit the temporary wood spacers and their protective pads.

Tool Footing Spreader 

Do corners

Measure the dimensions needed for the various corner pieces and cut them to fit.  The cutting is done freehand on the hotwire cutter bench after first marking the flat side of an assembly piece with a permanent marker pen.

This piece is for a concave corner in the outer EPS assembly...

Cut Freehand Eps Outer Inside Corner 

...and this is for a convex corner...

Convex Corner Eps Freehand Cut 

Put the corner pieces in place to make sure they fit.

Fitted Cut Outer Eps Inside Corner 

Squirt foam gap filler into the join to glue the corner pieces in place.  You may need paving slabs (on protective pads) and/or wooden props to keep the corner pieces in place while the foam is setting.

Foam Gun Pressed Into Crack Paving Slab Holding 

Foamed Outer Eps Concave Corner 

Foam Glued Outer Eps Convex Corner 

After the foam has set, trim off the excess with a 9mm long blade craft knife.  Be careful not to accidentally cut the polyethylene sheet.

Footing Eps Glued Proped 

Site Outside Footing Eps Some Inner 

Also measure, cut, and fit the EPS for the corners on the inside of the footing trench.  It is good to make the corners somewhat rounded by using 45 degree cut infill pieces of 2" EPS at the corners.

In the case of internal wall footings you can use pre-glued assemblies on one side (the nominally outside edge) as it won't stop you adding the EPS at the bottom of the footing..