Seating Manufacturers and Upholstery Shops find upholstery from LDI Interiors easy to work with and for the last 15 years have seen their skilled craftsmanship in creating finished products result in a well-tailored appearance long after installation.
While we are not upholsterers, we work with some of the best in the world, and we try to listen and share best practices.
With hundreds of designs utilizing similar formulation and construction, and many years of wide industry use, a designer is able to have confidence that their seating manufacturer or upholstery shop is able to achieve consistent results every time.
Here are a few upholstering tips to help minimize sagging or puddling issues:
- Take care in selecting pattern size when you cut materials. Our wipeable, coated fabric upholsteries have more inherent stretch than woven textiles, so patterns should often be adjusted smaller in size to compensate.
- Ecolution™ stretches different than EnviroLeather. EnviroSil™ will stretch different than as well. Different does not mean bad. It just requires attention be paid.
- It is all about creating tension and maintaining that tension over time. You have to pull in all directions so that you are applying some stress against the inherent stretch so that it can act like an elastic.
- Use high quality, high density /resilient (see foam selection section below) foam and ensure stress points, such as tight corners, are well padded.
- Consider cutting the foam at least one inch oversize in both directions.
- Thick foam applications should have breathing holes to allow for maximum foam recovery
- Consider using a bonded Dacron between the material and the foam to give the material some loft and assist the backing fabric to slide freely over the foam. This will assist in recovery when someone sits on it.
A couple misconceptions that we would like to clarify (we listen and learn!):
- The TPE face of EnviroLeather™ by itself has more elasticity to it than the PVC face of Ecolution™. However, we have come to learn that in actual use, the support substrate (the backing) is the determining factor about how elastic a product is. In other words, regardless of the chemistry of the coated fabric face, we are going to control sagging via the substrate.
- There is an test method (SAE J855-2009) for stretch and set that many people rely on to say 1 material is less susceptible to sagging than another. You cut a piece of material into strips in various directions, hand a weight from it, measure the “stretch %” and then release it to see how close to the original length it returns to, which is articulated as the “set %” in that direction. The problem with using this test to try to correlate to minimizing sagging is that with high stretch materials you never “max out” the stretch on an upholstered chair. The substrate fibers on high stretch materials may never see the amount of pressure that is applied…because they stretch further than the cushion allows them to! We have developed tests to more closely mimic the force material experiences in a chair application and we test to ensure they recover. We quantify it in terms of time to give us a comparative test method that more closely mimics the real world.
Avoid Abrasion Issues
Here are a few upholstering tips to help minimize abrasion issues:
- Ensure stress points, such as sharp corners or edges are well padded.
- Whenever possible, avoid or minimize right angle seams in high abrasion areas. For example, use a waterfall design vs edge seam along the chair cushion bottom
- Consider double stitching key seam areas, but stitching back and forth over the same line could simply cut the top film
- Consider using 7-8 stitches per inch using a light ball tip needle. Ideal size is 19 American / 120 European. Thread and pressure should be set up to be as loose as possible.
- Ensure that the foot on the sewing machine is not grabbing the material as it passes through. A little Teflon tape on the machine can help if this is a problem.
- Avoid use of welt cord, especially if the welt cord is in an exposed, high abrasion area such as a cushion top. Wrapping a piece of fabric around a hard, plastic tube exposes it to continual rubbing every time someone sits down and gets up. Also, the welt cord creates greater tension on the material. This reduces the flexibility of faux leather and makes it easier to abrade the surface of the material.
Foam Selection Tips
The ILD or IFD – Indentation Load/Force Deflection - rating impacts the feel of the foam, and tells you how much weight it takes to compress the foam by one third. The lower ILD/IFD foam will sit softer. The higher ILD/IFD foam will sit firmer. ILD/IFD numbers range between 15 and 55. Foams suitable for seat cushions are typically rated 35-55 but the thickness of the foam should also be taken into consideration since you can bottom-out more easily on softer/thinner foam. People often confuse foam density (lbs/cubic inch) with firmness but foams of different firmness can have exactly the same densities. There is a correlation with the quality of the foam and the density. High Resilience foam, or HR foam, is open-cell, flexible polyurethane foam that has a less uniform (more random) cell structure that helps add support, comfort, and resilience or bounce. HR foams are considered the highest grade and have densities of 2.5 lbs/cubic foot or greater.
California TB 133
Cal TB 133 is a composite test that evaluates a fully assembled furniture system. There are many variables which affect the result of this test, such as surface area, contour design and component materials such as type of flame blocker and urethane foam used. Upholstery is only a component, so we cannot say if our materials pass TB 133 or not. It is the responsibility of the manufacturer to choose what components to use and to validate performance for TB 133 on the appropriate assembled furniture system. The same material can pass on one chair and fail on another due to the variations in furniture construction listed above.
Recommendations for success:
- If you require a flame blocker we suggest gluing the blocker to the back of the upholstery vs. “double covering”. Take care to ensure the bond is strong to avoid the two materials breaking apart after installation, which could lead to wrinkles in the material.
- Whenever possible, if a flame blocker is necessary, try to select one that does not contain halogenated flame retardants. While they perform well, they contain toxic chemicals that have been shown to impact human health. Non-halogenated options exist.