Choosing the best foam to reupholster a chair is not as easy as it might seem. Density and compression are the key elements in how foam is sold and categorised. Density defines the thickness and compression defines weight resiliency. Additional considerations include indoor versus outdoor use, exposure to water and precautions as to whether the chair needs to be fire retardant.
Open Cell Foam for Interior and Home Use
The best overall choice to satisfy most indoor furniture reupholstering needs is to go with a medium open-cell foam, for heavier chairs such as those made of wood, chairs used in a dining room or for more "cushiony" chairs such as those used in a living room. The foam should have a density of 2.1 or higher and accommodate a compression weight of at least 15.4kg. If the chair is lighter, like a kitchen chair, a light, open cell foam with a density of 1.0 and a compression capacity of 13.6kg. is the best choice.
Mildew Resistant and Quick Drying Outdoor Foam
Upholstering a chair for outdoor use by pools, patios and garden spaces requires additional considerations. This will be especially true for chairs placed outdoors in humid climates and areas that experience heavy rains. Mildew will be the most common threat. As a result, the best choice is an open cell foam that has a higher density of 2.0 or more and a compression of 24.9kg. This will enable the seat cushioning to accommodate and expel water, and be wrung out to dry quicker, with minimal loss of resiliency.
Outdoor and Marine Quality Foam
Open cell foam is also the best choice for upholstering outdoor and marine chairs. The caution is to be sure that the foam has the correct density and compression capacity and, most of all, that the foam is mildew resistant. The best cell foam choices should have a density of 1.5 or higher to reupholster common outdoor garden furniture seat cushions, and 2.0 and higher for cushions used on boats. Compression is also a key consideration for upholstering seating for boats; the best choices should have a weight capacity of 20kg. If the chair will have a dual purpose to serve as a flotation device, the best foam should have a high density of 4.0 or more and a weight compression of 11.3kg. (lower than the compression weight for "land" or "on-board" use) to enable the upholstered seat cushion to float in the case of an emergency.
High Resiliency Foam for Public Places
High resiliency foam is best for upholstering chairs that will be used frequently, as in public places such as restaurants. High resiliency foam should have a density of 2.85 or higher and a compression of 24.9kg. or more. Look for high resiliency foam that is also fire retardant for upholstering chairs that will be used frequently by the public. Additional considerations are mildew resistance and antimicrobial capabilities for upholstering chairs used frequently and by public patrons and business customers.