Carpet Construction and Materials
What the exam tests
Construction and materials questions check whether you can match a repair method and seaming method to fiber, pile, backing and dye method. The exam expects you to recognize how the carpet was built, not just its color.
Core rules
- Tufted carpet normally has a primary backing, tufted yarn, latex precoat and secondary backing or attached cushion. The precoat locks tufts; delamination usually means the precoat-to-secondary bond has failed.
- Pile types include cut pile (plush, textured, Saxony, frieze), loop pile (level loop, multilevel) and cut-and-loop. A pulled loop should be worked back through the backing, not clipped off.
- Fibers differ: nylon is strong and resilient; polyester resists staining but crushes; olefin resists moisture but is heat-sensitive; wool is naturally flame-resistant.
- Density is commonly estimated from face weight and pile height. Gauge is needle spacing and stitch rate is tufts per inch; higher density generally improves wear.
- Dye method matters. Solution-dyed yarn is colorfast; stock-dyed or piece-dyed carpet may fade and may not match a patch.
Worked example
A loop-pile Berber has a pulled loop beside a seam. A helper wants to clip it flush. Reasoning: clipping a loop leaves a visible gap and can unravel the row. The correct repair is to pull the loop back through the backing with an awl, apply seam latex or adhesive at the base, and trim only the frayed tip after the repair is secure. If the yarn is broken, re-tuft with matching yarn and seal it.
Traps
- Using the same hot-iron setting on olefin as on nylon.
- Matching color but ignoring pile height, gauge and dye lot.
- Treating every backing as attached cushion and skipping tack strip.
- Cutting a loop instead of re-tufting it.
Key points
- Know the layers: primary backing, precoat, secondary backing or cushion.
- Identify cut pile, loop pile and cut-and-loop before choosing a repair.
- Match fiber heat sensitivity to seaming temperature.
- Density, gauge and stitch rate affect wear and repair choice.
- Solution-dyed yarn is the safest match for colorfast repair.