Installing Natural Fibers, Part II
April 8, 2005
In the April 2004 issue of FCI, in my article "Installing Natural Fibers," we looked at several different types of natural fibers, weaves and general installation procedures. In this issue we will go through the installation process of a seagrass fiber and recap some of the installation tips from natural fibers part one. Before you begin any installation of natural fibers you will need to first know which type of product that you are installing, such as sisal, coir, sea grass, mountain grass, cellulose, maize, etc. Second, the manufacturer's installation guidelines need to be followed.
Photo1 shows two different types of backings that are commonly used with natural fibers. The top backing has an attached cushion for a bit more comfort underfoot and is direct glue down installation only. The bottom backing is more for dimensional stability and to minimize adhesive bleed through. The bottom product can be installed as a direct gluedown or double stick installation, check with the manufacturer for double stick installation procedures.
Natural fibers are very pliable, which makes keeping patterns or lineal lines more difficult to align then some of the more conventional types of carpet, as seen in Photo 2, which shows a dry line strung across the width. Photo 3 shows the process for setting up the dry line. Establish the match points at each end and then run a dry line to create a straight line (Photo 4).
Using "reinforcing nails" behind the pilot nail instead of fastening the dry line to the pilot nail, this minimizes the potential of the pilot nail breaking free from the tension of the dry line; this works on both wood and concrete.
Photo 5 shows Jesus Rosas matching the pattern with a knee kicker to the dry line and placing stay nails approximately every four feet or wherever required through the floor covering. Layout of dry lines may be necessary in both the length and the width to keep the pattern aligned which means that you may have to spread adhesive in smaller sections.
Use the proper-notched trowel and adhesive that the manufacturer recommends, roll with proper weight roller (Photo 6). Using a wall trimmer designed for glue down type installation works well as natural fibers are more difficult to trim (Photo 7).
Trimming with a knife can pull the pattern if the adhesive has not set up enough and create an arc at the wall. It takes quite a bit of finesse to use a knife because the natural fibers do not cut as easily as many carpets. Using a knife for extended periods to trim excess along walls can lead to carpal tunnel.
The knife that I use when trimming to door casings and small areas is a utility knife, The rigid chisel point helps cut through the fibrous strands better than a slotted carpet blade. Quarter-round or wall base makes for a clean finished edge along walls and baseboards. You can also attach edge-binding material around the perimeter to create a unique look; we'll cover this in another article.
If you have seams, follow the manufacturers' recommended seaming procedures (Photo 8). Trim far enough into the selvage edge to create a seam with the rubber membrane intact (Photo 9). Using a top row cutter to cut the seams is easier than using a loop pile cutter, the loop pile cutter can snag strands of fiber, pulling apart the weave (Photo 10).
Shears are a must-have tool when working with natural fibers; ten- or twelve-inch shears work great. After cutting with the top row cutter, it may be necessary to follow with shears and cut any fibers that are still attached to the seam edge. It may be necessary at times to use shears to cut the entire seam edges. When trimming the seam edges, remember that there will be unsecured warp (length) and weft (width) fibers. Match the seam to where these fibers will have the least tendency to break free.
A universal acrylic sealer works well in the right application; it can be used to seal the edges prior to installation and then as a seam sealer when constructing the seams; it also dries clear and hard which means it is somewhat forgiving if you do happen to get it on the face pile. The problem you may encounter with an acrylic is that it may not adhere to the fiber. Seagrass, which has a thick, rigid and smooth texture, requires using either a contact or similar type product. Apply a small bead, and then evenly spread with a small stiff brush (Photo 11). Avoid latex, unless the manufacturer states otherwise; it can be a soil attractant as it remains tacky for life and some products require quite a bit or very little, depending on the thickness. Latex on the face fibers can lead to problems because it is very difficult, or impossible, to remove. Acrylics can be cleaned with a cotton towel dampened with water while they are wet. If using the solvent-based sealers (amber colored) be careful as some can cause discoloration of the fibers. A safety solvent works well to remove any excess adhesive from the face pile, a citrus solvent is not recommended.
In the April article we advised avoiding cross seams with natural products; once again, avoid cross seams whenever possible. With the weaving process, the warp fibers run continuously along the length and when cut they make for a visible cross seam (Photo 12). Photo 13 shows a well-constructed length seam. It's a good idea to take a small scrap piece of product prior to installing and see how it seams up.
A threshold is what I like to recommend at doorways, but what if the end user does not want to use a wood or tile threshold. Photo 14 is an example of what can happen with any cut fibers. Even with seam sealer it is difficult to keep the ends from breaking loose. Thresholds help aesthetically, but the end cuts can still break loose on these as well. Here's a tip to minimize the ends breaking loose when butting to a threshold or when you have no choice but to construct a cross seam.
A hot glue gun (Photo 15) works well to bond the end cut fibers on new installations and repairs of loose strands on installed jobs. The weft (width) fibers on a length seam depending on the product may require a small amount of hot melt. Apply a small amount of hot melt, just enough to hold the fibers in place. Be careful not to use to much as it requires very little for a bond. You can also use non-flammable contact with a small brush but I prefer the hot glue method with little to no odor. For maintenance, follow the manufacturer's recommendations (Photo 16). There are products available that can help maintain the beauty of natural fibers.
More installation tips:
• Know what you are installing.
• Read the manufacturer's instructions.
• Moisture test before installation.
• Allow extra material in both length and width to work with.
• Acclimate the product; lay out in the room if possible.
• Choose a seam sealer that is compatible with the product.
• Use a dry line.
• Ten or twelve inch shears
• Wall trimmer for glue down carpet
• Hot glue gun
• Utility knife
• Quarter-round or wall base
• Bid the job right! This is a custom installation; it takes time, patience, and a qualified installer to work with this type of product, which means more money.