RV Mods: Upholstery foam sagging? Give it the bum’s rush!



By Russ and Tiña De Maris

If you’re an RV manufacturer and need to save a few bucks, where do you shave? One oft’ done area is where the rump meets the road – the quality of foam rubber in cushions. A few years down the road, and sitting down at the dinette may be an exercise where you feel you need a parachute for a soft landing. Taking the bumps out of your bum doesn’t necessarily require hiring out an upholstery professional — in many cases you can do it for less yourself!

The most common foam job for RVers is doing booth-style dinette cushions. In most instances the dinette can double as a bed, and we’ve found from bitter experience that if you replace the foam seat cushions, it’s best to replace the back rest foam at the same time.

Take a look at your cushions: Most are not sewn completely shut but, rather, are equipped with a zipper along one side to make changing out the foam a breeze. Step one: Unzip the cushion and pry the foam out. This probably requires carefully pulling the casing down on each side a little at a time, then pulling down the opposite side in a similar way — as opposed to trying to pull one side down all the way in one whack.

With the foam free of the foam casing, carefully measure the thickness of the foam in more than one place along the cushion. You may find that the pressure of being sat upon, and being trapped in a tight casing, may cause seeming irregularities in thickness. Typically cushions will be at full or one-half inch thickness increments. Now measure the length and width in a similar fashion. You can measure the fabric casing — simply add a half inch to each dimension to determine the size of foam you’ll need.

You may find a layer of white wispy stuff on your existing foam rubber. This is a Dacron wrap. Some manufacturers will simply slip it around the foam, others will glue to the foam. It may be that you can reuse the existing wrap (if it’s loose). An upholstery pro tells us that the wrap is added to make the finished product look less wrinkly, and to fill out corners. Ad copy tells us that it also “lengthens the life of the fabric,” and make it easier to stuff the cushions into the fabric casings. We’ve opted not to buy additional Dacron wrap — part of our thrifty heritage.

Now that you have foam sizes down, what else do you need to know about foam? A couple of things are useful. The most important is knowing the foam density, which is a great indicator of durability. Density is measured in pounds per square foot: The higher the number, the denser the foam, and the longer it should last. Typical furniture-grade foams start at about 1.8 pounds. The other figure is for compression, translating how firm the foam is. Measured by an “ILD” number, the higher the ILD, the harder the foam. If you’re going to sleep on it, you’d probably be best to visit a foam retailer to “feel” for yourself what you want.

Still, you can buy foam via the Internet and some excellent bargains are out there. We found that typically Internet retailers talk about the quality of their foams in non-standardized ways, like “Premium,” or “M-38,” or “Our Best,” all screaming for your dollars. Simply phone the outfit and ask for density and ILD numbers. If they can’t tell you, look elsewhere.  You’ll have to factor in the cost of shipping when making a decision based on the budget.

If your foam is shipped to you, it’ll likely come compressed in a tight package. Don’t leave it in the original package — release it from bondage immediately, lest it be damaged by being compressed too long. Best to let it sit overnight before working with it. If you decide to skimp on the Dacron wrap, you’ll find it easier to have a helper assist you to stuff the new foam in the fabric casing. Like taking the old out, putting the new in is a matter of not biting off more than you can chew. Work the foam in, bit by bit, maybe even starting with the casing inside-out.

With new foam in your cushions, your tush will thank you!



  1. Most dinettes have such poor foam in the seats that it almost calls for going directly to your favorite re-upholsterer (or foam store for DIY’ers) right after you leave the dealer.

  2. If you need to cut the foam, here’s a trick I learned from my wife’s brother. Get an electric carving knife from a thrift shop. the dual reciprocating blades cut the foam quickly and without pulling at it.

  3. I recently made new upholstery for my dinette. A trick for fitting the foam back in the fabric: slip on the largest plastic garbage bags you can find, insert into fabric, then reach in with arm and pull out plastic. Works like a charm without the huge struggle!

    • The plastic. that dry cleaners wrap your clothes in works the best. You can leave that on the foam and no crackling noise.

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