Installation Guide

The Fastfoot® footing membrane is a cost effective and green method of forming concrete footings. This installation covers strip footings where a single width of Fastfoot® is used to form both sides of the footing. For a PDF of the installation guide, click HERE.

For wider footings or for deep pads where Fastfoot® only forms one edge of the footing or pad, click here: EDGING INSTALLATION.

To estimate the Fastfoot size and quantity, click here: FASTFOOT ESTIMATOR.

Tools & Supplies

1. Sharp scissors;
2. Hammer tacker with 3/8" staples;
3. 2" sheathing tape;
4. Stakes (either 1x4s, 2x4s or metal stakes, depending on ground conditions);
5. Hammer for driving stakes;
6. 1x4s for cleats;
7. Laser or builder's level for setting height on stakes.

Understanding Fastfoot® Widths

Fastfoot® comes in three widths:

• FF50 - Narrow, 50" wide, suitable for footings up to 18" wide and 10" deep
• FF62 - Standard, 62" wide, suitable for footings up to 24" wide and 13" deep
• FF74 - Wide, 74" wide, suitable for footings up to 36" wide and 13" deep

Deeper footings can be accommodated wider fabric. Where necessary fabric can be run down each side and the two fabrics nailed into ground to prevent slippage. Note: if the fabric height is greater than 15", install a second 2x4 to reduce the bulge and fabric tension.

FABRIC WIDTH SIZING RULE - Width required = footing width + 2 x footing height + 10".

To estimate the Fastfoot size and quantity, click here: FASTFOOT ESTIMATOR.

1. Setup Screed Boards

Layout the outside footing stakes (steel or 1x4s) around the perimeter of the foundation using a string line. Drive the stakes on this line about 6' on center. Reduce spacing for deeper footings or when the ground is less dense.

Drive the inside stakes opposite each outside stake using a 1x2 cut to the footing width.

SOLIDLY attach screed boards to stakes. Fabric tension wants to torque the screed board off the stake. Use two angled nails or one screw per stake of sufficient length to penetrate the full depth.

2. Determine Stapling Location on Screed Board

Fastfoot® easily adjusts to different footing depths. Note: the Fastfoot width lines do NOT match the distance away from the centerline of the footing. This is because of the bulge in the fabric when filled with concrete.

Determine the correct location of the fabric edge on the screed board by:

• Place one hand on correct 'Fastfoot width line' on ground and bring fabric edge snugly over the screed board. Using a hammer tacker, staple Fastfoot to the top of the screed board approximately 6" on center (tighten spacing for deeper footings).
• Note the location of a colored 'edge line' with respect to the screed board under the fabric. Use this 'edge line' to position the fabric for stapling AS LONG AS the footing depth stays the same.
• If the footing depth increases, let the fabric OUT by placing hand on the same 'width line' and note the new edge line over the screed board.

3. Install Corners

Using the edge line as determined in step 2, staple both corner edges to the top (or back side) of the screed boards at 12" on centre, using a hammer tacker with 3/8" staples. If the footing depth increases, reduce the staple spacing accordingly.

If sewn corners are not available, click here for folding Fastfoot® on corners.

4. Install Straights

Hammer tack two edges of the Fastfoot® roll on top of the corner fabric with a 10" overlap. Unroll past next corner and cut with a 10" overlap. Hammer tack both top edges 12" on center using the predetermined edge line.

Nail center line to prevent movement by wind and concrete. Use sheathing tape on overlaps and nail holes to prevent concrete escaping from and moisture entering footing. If the ground below the fabric will not support a nail (granular fill or sand), a brick or stone can be used to prevent fabric movement.

T-Junctions

Run fabric through junction. Cut an inverted 'T' in junction area with lower cut along footing width line equal to the width of the footing width lines. Fold and staple tabs.

Run intersecting fabric into junction allowing a 10" overlap. Cut overlap along footing width line, and staple overlapping tabs to screed boards.

Steps

Drive pairs of 2x4 stakes into the ground and nail (or screw) to upper and lower screed boards. Drive additional stakes if the distance between the stake and bank is greater than 15". Install lower level Fastfoot®.

Run Fastfoot® up bank to form step. If step is too deep to form with a single width of fabric, either run two widths of fabric (edging) or turn the fabric 90 degrees to obtain the required width.

Install the upper level Fastfoot® with a 10" overlap past top of step. Cut the overlap on the footing width lines, letting the center portion hang down bank.

Screw plywood bulkhead in position and brace. Note that the fabric can also be installed without cutting. Place a fold on the top edge equal to the height of the footing at that point.

Widened footings - Step I

Creating widened footings is easy with Fastfoot.

First, run the main fabric  (gray color) between the screed boards and staple in place. Using scissors, cut the fabric at the start and end of the widened opening as shown and lay the cut extension on the ground.

Then take a small roll of Fastfoot and cut in half with a chop saw. For example the 62" Fastfoot will then become two small rolls, each with a width of 31" when unfolded.

Widened footings - Step II

Take the the half width roll and edge form the extended footing as shown using your hammer tacker. Use sheathing tape to hold the bottom edge in position.

For more information on edge forming with Fastfoot, click HERE.

Coefficient of Static Friction

With most foundations, the soil loads on the foundation walls are symmetric around the perimeter. However, for foundations on slopes or with retaining walls, there may be significantly higher loads on the one side. Fastfoot may reduce the coefficient of static friction and the engineer may want to ensure the resistance of the footing to the soil is sufficient to withstand the eccentric loads.

Usual remediation is to dig a small keyway under the fabric so that the poured concrete is locked to the soil below.

For the actual angle of resistance of Fastfoot (32 degrees), see the testing report.

Damp Proofing

Concrete is 'hygroscopic', meaning ground moisture wicks up through the footing concrete and inside the building. Fastfoot® is a vapor barrier which prevents this wicking.

After pouring the footing concrete, leave screed boards in place to hold Fastfoot® in position. Pull Fastfoot® off screed boards and lay under wall forms. Use 2" sheathing tape to hold in position. Form and pour the foundation wall.

Then run a 12" width of 'Peel & Stick' along top of footing (covering any staple holes in Fastfoot®) and up the side of the wall. Lap bottom edge of wall membrane over vertical 'Peel & Stick'.

On the inside of the footing, tape the under slab membrane to Fastfoot®.

Click here for more information on rising damp.