Install a Fence

Does this look familiar to you? Broken fence, rotten, wind damaged fence posts…you may want to repair it or save time and effort building a brand new fence. In both instances, Sika has developed a product that fundamentally changes the way people can install or repair their fence.

The Concept (in a nutshell): Sika® Post Fix is an expansive polyurethane foam specifically formulated and packaged to provide a lightweight, mix-in-the-bag, fast-setting and high-strength material for installing fences and other in-ground supports.
 

Sika® Post Fix is:

• Solid as Concrete… Thanks to its ability to expand in all directions in the hole and adhere to virtually anything in the ground (rocks, roots, etc.), Sika® Post Fix offers an excellent pull-off resistance and will perform equally as well as — if not better than — concrete. For replacing posts, it is far easier to work with than concrete.

• Winter performance… One may wonder about the performance of Sika® Post Fix under our harsh Canadian climate: Will the posts resist to the freeze and thaw phenomenon (frost heave)?
• Freeze-thaw behaviour… Provided the municipal  building code requirements (for hole’s depth) have been observed, Sika® Post Fix will resist to the freeze and thaw phenomenon.
• Wind resistance… The polyurethane foam is a high strength material that can take some compression and, for example, absorb wind gusts and then come back to its initial position.

Sika® Post Fix: One 979 mL pouch yields approx. 20 L (0.7 ft3) of expanded foam.

In comparison with concrete, it means…

Let’s take a standard 25-post fence job, your project will require:

• 50 bags of concrete mix (count 2 bags of concrete mix per post)
• 25 posts x 60 kg (2 x 30 kg/post) which adds up to 1.5 ton of concrete mix…

There’s always the option to have the concrete bags delivered to your home (add
delivery costs $$)… but to your front door… But make sure to have friends available that day to help you carry the bags to your backyard…

Or if you like to do things on your own, love to get dirty, and hopefully not hurt your back, you can always rent a pick-up truck (add truck rental cost $$ and a couple of trips, plus lost time in transport…)

And by the way, even if you own a pick-up truck, at 1.5 tons, you may want to check its payload capacity… Chances are, you may have to do a couple of trips… and maybe rent a mixer at your local equipment rental outfit ($$).

1. Check your local Building Code for frost depth in your area (it will determine the depth of the holes)
2. Read the product data sheet and directions on the packaging before starting
3. Product temperature: Sika® Post Fix temperature must be between 18 – 25°C for at least 2 hours before using (keep in mind that the average temperature of a garage slab is 14°C, if your material is stored directly on the ground, it will be at the same temperature… 14°C! notice that 4 degrees make the whole difference in terms of product performance)
4. Make sure the holes are free of standing water: If there is standing water in the hole, backfill partially with soil or gravel until water is no longer visible or pump the water out
5. Respect the 20-second mixing time
6. Don’t move the posts beyond the first 10 seconds following the initial pour (don’t hesitate to use a bracing device to immobilize the post in the hole)
   

Here is a quick and easy tool to help you calculate the number of bags you will require for your project…

Tools you won’t need… Wheelbarrow, shovel, trowel, buckets, concrete mixer, hose and a water line… Not to mention enlisting friends and family members for the operation! Just invite them over to enjoy the backyard once the job is completed!

Whether or not to use builders’ tubes (Sonotubes®)… Actually, and contrary to the common belief (or practice) when it comes to excavation for fencing, the use of builders’ tubes is actually not recommended with Sika® Post Fix, here is why:

1. Since they may be made of recycled material, builders’ tubes may be coated with a variety of materials that can prevent Sika® Post Fix from bonding to the tube.
2. Builders’ tubes prevent the multidirectional expansion of the polyurethane foam into the voids, cavities, asperities or any irregularities in the hole which give the material a better adherence or ‘’grip’’ and may also prevent frost heave. The packages are proportioned to expand to 1 cubic foot of material (most concrete yields 1/2 a cubic foot per 50 lb bag) which is what is required to backfill a hole 4′ deep 8″ diameter containing a 4″x4″ fence post.  

Sika Post Fix expands in all directions in the hole and adhere to virtually anything in the ground (rocks, roots, etc.)