best-sofa-supension

Quality Sofa Construction: Springs & Suspension

Ensuring your new sofa has been created with the right, quality materials is crucial if you are looking for a long lasting sofa. 

However, the frustrating part of shopping for a new sofa is that they all look the same – just with different names and price tags! Often the differentiator is hidden under the fabric in the frame, suspension and foam. 

Below we explore the different types of springs or webbing used in the cushions that are commonly used by furniture manufacturers. Be sure to also check out our blogs on selecting the best fabric for your lifestyle,  what is the best foam for long lasting cushions, and the power of a good frame

What is the Purpose of Suspension?

The springs inside your sofa are used to absorb shock and can provide firmness and elasticity for the seat of the couch. The quality of springs used works together with the quality of the foam and framing. They are like one big team holding you up while you read your favorite book, or have a movie marathon with the family. 

4 Types of Suspension

Pocket Coil Springs

You’ve probably heard this term quite a bit, especially when relating to mattresses. This type of spring tends to hold it’s shape better and support better over time. Generally, pocket springs will last a long time which is perfect for those who value longevity in their sofas. 

Sinuous Springs

Also referred to as “S” springs, this is the most commonly seen suspension system in mid-tier sofas. Made with heavy gauge steel wires bent into a continuous line of vertical S shaped coils. Horizontal metal tie rods reinforce the coils, inhibiting shifting and sagging. Typically a heavier gauge steel is used and a greater number of springs with few spacings provide more comfort.

Webbing

Web suspension is a design that creates a sofa cushion support similar to a hammock. The strips are stretched across the seating frame and tacked into place to provide support for the cushions.

8 Way Hand Tied Springs

This is considered the ultimate choice in high-quality sofa construction. Using a heavy guage steel coil at the base, a craftsman then works with high quality twin to tie each coil spring together, crossed in 8 different directions. This process helps guarantee sturdy support and limits individual sagging of any one spring over the lift of the sofa.

Which Type of Suspension is Best? 

There are 2 clear winners for the best type of suspension to be used for a sofa – Sinuous ‘S’ Springs and 8 Way Hand Tied Springs. The determining factor in deciding between the two is simply cost. 

Because of the labor involved in creating an 8 way hand tied spring, this will significantly raise the cost of the sofa. It will however also extend the longevity of the suspension. 

If you still want to invest in a quality sofa, but maybe don’t want to spend as much as you would with the above springs, then purchasing a sofa with Sinuous Springs is also an excellent choice. The spring construction is solid, and will last many many years. 

sofa-frame-construction

Quality Sofa Construction: The Power of a Good Frame

Ensuring your new sofa has been created with the right, quality materials is crucial if you are looking for a long lasting sofa. After all, if a house is built on a subpar foundation, no matter how pretty it is, it will crumble. 

However, the frustrating part of shopping for a new sofa is that they all look the same – just with different names and price tags! Often the differentiator is hidden under the fabric in the frame, springs and foam. 

Below we explore the different types of framing material and construction methods commonly used by furniture manufacturers. Be sure to also check out our blogs on selecting the best fabric for your lifestyle, the best sofa springs & suspension, and what is the best foam for long lasting cushions

The Material

sofa-frame-construction

Before we get talking about how a sofa frame is built, let’s talk about the materials being used to build that frame. 

A slower growing, denser hardwood such as alder, poplar, maple, teak or walnut are considered more suitable for durable and long lasting furniture. 

Softer woods such as pine or douglas fir are still good, but won’t hold up as well as a harder wood species will. 

Some manufactures will use fiberboard or particle board in constructing their furniture to keep costs down. The issue with using a material such as this, is that there is basically zero structure or strength meaning it cannot support heavy loads. 

The reason why it is so important to get the wood material right is because you want a wood that will hold the staples, nails, glues and joinery in place. The harder the wood, the better it will grab and hold onto whatever item is holding it together. A softer wood is more prone to movement, and overtime will wear down. 

Kiln Dried Wood

You may see from more high end manufactures that they use kiln dried wood. But what does that mean? 

Kiln drying is a procedure done to remove all moisture in the wood. Moisture can be a big problem with wood, as it will cause the wood to warp or crack. And having a frame that warps or cracks is never good. 

The Construction

How is a sofa made? Well like any other structure really. It’s made by joining pieces of wood together. Therefore the sturdiness of the joints play a huge factor on if the furniture piece will get wobbly. Below we have high lighted a few of the more common joint types you may find in sofa construction. 

Solid Joint Types:

  • Mortise & Tenon Joint – This is considered the strongest type of joinery. It is mostly used in table construction to adhere the legs to the top for a solid surface. One piece of wood has a hole, and the other is cut to fit precisely into that hole. 
  • Dovetail Joint – This type of joint is not only strong, but also looks great too. It is commonly used in drawers for cabinets. 
  • Box Joint – This joint is made by cutting a set of matching rectangular cuts into 2 pieces of wood, which are then glued together. It is often used for boxes or chests because of it’s decorative look. 

Not So Solid Joint Types:

  • Butt Joint – This is the simplest type of joinery, but also the weakest. It joins 2 pieces of wood by merely butting them together and then attached using glue or with a nail or screw. 
  • Dowel Joint – A dowel joint is similar to the butt joint, except dowels are used to secure the pieces together. A dowel is a small wooden cylinder that gets inserted into a small round hole drilled into 2 pieces of wood. It’s not as sturdy, and will more likely loosen over time, however it is an acceptable joinery method.
mortise-tenon-joint
Mortise & Tenon Joint
dovetail-joints
Dovetail Joint

Additional Reinforcements:

To create an even stronger frame for a sofa, most manufacturers will use extra reinforcement. You may see terms such as Corner Block Reinforced, or just Reinforced Joinery. 

When there is a corner, adding an extra piece of wood that is placed at an angle and screwed into place will help ensure the piece of furniture is stable for years to come. 

Additionally an extra layer of support may be added with glue, screws or staples. 

Remember These 3 Things When Buying a New Sofa

In summary, when you are searching for a new sofa keep in mind it’s what underneath the fabric that counts the most. Typically a lower price tag means lower quality materials have been used, which will result in a shorter lifespan of the item. 

Remember these 3 things:

  1. What type of wood was used in the construction? Hardwood = longer lifespan and greater return on investment.
    Softer wood or particle board = shorter lifespan, but easy on the wallet. 
  2. Has the wood been kiln dried? This is an important step in the manufacturing process as it dries out the wood, which will prevent warping & cracking. 
  3. What type of joinery & reinforcement has been used? Look for a joint that has been cut with precision, and essentially slotted together (almost like intertwined fingers) and then corner blocked. Stay away from a simple butt joint. 
sofa-foam-cushions

Quality Sofa Construction: It’s All in the Foam

In this blog we will be exploring what type of foam is best for your sofa cushions. After all, isn’t the point of a sofa to be able to sit comfortably on it for years to come?! 

When shopping for a sofa, there are a few things you should look for before making your purchase. The 3 biggest factors in determining if your sofa will be long lasting is the frame material & construction, the springs and the cushion foam density. Additionally, selecting the fabric that is right for your lifestyle can play a huge part as well. If you haven’t already read our blog on the types of fabric, click here to check it out!

best-foams-for-sofas

What does density mean?

When looking at the material specifications of any new sofa, they will generally tell you the foam density in a ‘pound per cubic foot’ measurement, or pcf for short. 

But what does that even mean? 

Density is simply a measurement of weight per unit of volume. In the case of foam it is measured in pounds per cubic foot (PCF). In other words, the density of foam is expressed by measuring the weight of a single cubic foot of foam material. 

Foams with a higher density will generally feel more firm, and can withstand more pressure. Foams with a lower density will be softer but not as durable. 

Therefore, for a longer lasting and more durable cushions you should go with a sofa that is made with a higher pounds per cubic foot measurement. 

There are 5 main types of foam or fills typically used in sofa construction.:

Standard Polyurethane
High Density Foam
Lux Foam
High Resilience Foam
Down & Feather

Keep reading for details on each of these foams or fills, and to find out which ones are considered the worst, and the best for long lasting sofas. 

Standard Polyurethane

Typically the pound per cubic foot of a standard polyurethane foam is 1.2 pcf. Sofa cushions made with this foam will not be very comfortable, or last as long as the other foams. It will last for about 1-2 years before you start to see deterioration and sink areas in your cushions. Additionally, the return rate to it’s original form is very slow. 

High Density Foam

High Density Foam is the most common type of foam used for furniture. It has a 1.9 pcf rating, but will still provide support and comfort just to a lesser degree than other foams. A high density foam will generally last around 4 years, but will get softer over time. The return rate to it’s original form is medium and it will offer a more consistent level or support and comfort than a standard polyurethane foam. 

Lux Foam

With a 2.2 pcf rating, a cushion with lux foam with provide a much firmer feel and will last around 6 years. This foam has a quick return rate to it’s original form, is durable and able to support various pressures. 

High Resiliance Foam

Made from a high grade open cell foam, a high resilience foam ranges from 2.5 to 3.0 pcf. This foam has a high responsiveness rate, and a quick return rate to it’s original form. Even though it is very springy, it still offers sturdy support and will last between 8 – 10 years. This type of foam is used in high quality sofa construction, and is the best foam type if you are looking for a long lasting investment. 

Down & Feather Fill

Even though it’s not technically a foam, most high end sofas have the option of adding down or feather fill cushions. These are a good option when combined with an inner foam core. Adding down or feather will make for a more comfortable cushion, however if combined with polyester fibers this could create lumps over time due to the fibers clumping together. 

Dacron Wrapped Foam

Some sofa manufacturers will add an additional Dacron wrap to their foam. A Dacron wrap is a polyester fiber that is used to prevent the fabric from creeping or slipping. Dacron will also help make the cushion look puffy and feel softer. 

In conclusion, typically the best foam to use for sofa cushions will have a pound per cubic foot (pcf) rating of between 2.0 to 2.5. The name of high density foam or high resilience foam can sometimes be interchangeable so we find it’s best to just look at the pcf number to determine the quality of foam used! 

At designQ, our sofa manufacturers use between a 2.1 to 2.75 pcf foam, depending on the style. Additionally, they will also do a Dacron wrap to help prevent slipping of fabric and to help the cushion maintain it’s shape! 

Happy Sofa Shopping!