when it comes to vinyl flooring I prefer a non interlocking glue down system of high quality above all.

I have heard that. We will have low-E windows, but how much of a worry is it? is it mainly fading? I believe SPC are better in sun?

My wife and I retired to AZ 10 years ago. We both have bad knees and she also has a bad hip. Our house in AZ has ceramic tile floors, except in the bedrooms. The house is built on a concrete slab. Talk about a hard floor! The solution to hard floors is to wear very soft spongy soled shoes in the house all of the time. There are a few models of Skechers shoes which have extremely soft soles. With these shoes, there is no need for carpet, rugs, or cushioned floor mats to eliminate the shock on the joints.

We are planning to remove the old carpet in all of the bedrooms. I’ve been researching flooring for the past 5 weeks and have decided to go with a wood-look rigid core vinyl plank that locks together to make a floating floor. (Beware, these interlocking rigid floors require a very flat subfloor. If the subfloor is not really flat, it will have to be flattened before the new rigid vinyl planks are put down. Might want to read the installation instructions before you buy the flooring.) As you know, most of these products have one of two kinds of cores, Wood Polymer Composite (WPC) or Solid Polymer Composite (SPC). SPC is also used to stand for Stone Polymer Composite. The polymer is usually PVC, in other words, vinyl.

It appears to me that most of the new rigid core vinyl plank flooring products that have been introduced during the past 7 years use an SPC core or some minor variation of it. That suggests to me that SPC is better or perhaps cheaper to manufacture. I have looked at WPC & SPC products. For some applications I don’t think it makes much difference. We will probably end up with an SPC product but not because of, or in spite of, the kind of core.

All of the products we’re considering have an attached underlayment/pad that absorbs a little shock. Some are cork, some EVA foam and some IXPE. Thickness varies from 0.5mm to 1.5mm.

SPC is more dense. It has less air in it. It expands and contracts less due to changes in temperature. Consequently it is better than WPC if the flooring will be exposed to a lot of direct sunlight, especially in the summer. It’s also best if the ambient temperature varies considerably, such as a house that is not heated and cooled year round. Because SPC expands and contracts less than WPC, SPC is better for very large rooms or long runs, say from one end of a house to the other end. SPC requires fewer expansion strips if you’re trying to cover the entire floor of a house with the same flooring product.

Floors made with SPC cores may expand and contract less from exposure to the sun, but that doesn’t make them more resistant to fading.

Makers of WPC claim that SPC is colder underfoot. I think the difference is undetectable or negligible, when touched by a bare hand. It’s totally irrelevant if you wear shoes or socks all the time.

Lastly, products made with SPC are more resistant to compression due to high pressure over a short period of time. I think this is a proxy for the pressure from very heavy furniture over much longer periods of time. SPC floors are also more resistant to sudden momentary impacts from heavy objects.

Today I tested 4 WPC products:

1. Home Depot Lifeproof, 7mm, 1.0mm IXPE pad, Dusk Cherry, #106204L
2. Lowe’s SMARTCORE Ultra, 7.5mm, 1.0mm pad, Savannah Oak, #1035196
3. COREtec Plus Plank 5”, 8mm, 1.0mm cork pad, Weldon Oak, #00509
4. Provenza, Uptown Chic, 8mm, 1.5mm IXPE pad

I’ve listed the color names when available but I don’t think the color affects the resistance to dents and impact.

I also tested 4 SPC products:

1. Armstrong PRYZM, 6.5mm, 1.0mm cork pad, Antiqued Oak Natural, #PC003
2. SUPERCore Xtreme, 6.0 mm, 1.5mm EVA pad, Wagon Wheel, #SPC023X
3. Flooret Modin Base, 5.0mm, 1.0mm IXPE pad, Kingswood
4. Karndean Van Gogh, 4.5mm, 0.5mm pad, Jatoba, #SCB42

Note that all of the SPC products were thinner than all of the WPC products

The first test applied 205 lbs to 0.02 sq inch on the face of each sample. That's about 10,000 PSI. The pressure was applied for 1 minute. All 4 WPC samples performed about the same. All 4 SPC samples performed about the same. Every SPC sample out performed every WPC sample. The dents on the SPC samples were extremely small, barely visible under very good light.

The second test involved dropping a steel rod from 2”, 3” & 5” vertically onto different spots on the face of a sample which was flat on a 4” thick concrete slab. The rod had a diameter of ¾” and weighed 3.5 lbs. It was 30” long with a 3/32” diameter point on the end. In all cases a longer drop resulted in a deeper and more visible dent. Three of the WPC samples performed essentially the same. The COREtec Plus didn’t fare quite as well. In this test the SUPERCore Xtreme slightly outperformed the other SPC samples, probably because of the thicker underlayment of SUPERCore. Again all SPC samples outperformed all of the WPC samples. The sheen, color, and texture of the surface, affect the visibility of the dents but not the depth. The thickness and kind of attached underlayment probably affects the depth of the dents slightly.

SPC and WPC planks can be made with the same wear layer, protective top surface coat, surface texture, surface sheen, edge detail, and attached underlayment. All of these attributes together probably affect how the product performs and wears. And of course resistance to impact is only one of many criteria upon which to choose rigid core vinyl plank flooring.

If you want a thick floor, you’ll probably want to go with WPC. If you want a quiet floor for the person walking on it with hard heels and soles, I don’t know. Probably won’t make any difference with rubber soled shoes. What do the rest of you think?

"but how much of a worry is it? is it mainly fading?"

That and the vinyl moves like made in direct sun. It will expand and contract a crap ton even with Low E Glass.

As long as the room is heated and cooled and proper spacing is used you should not have a problem. I do not like and will not use vinyl flooring that clicks together or used tape on it’s tongues. 10 years down the road when one the click locks breaks a tongue or groove you wil have to undo all tour flooring up to that point and probaly damage the other flooring as tou are unlocking or reinstalling . Hopefully they have the material you used at that point. all these floor have a hollow feel due to there floating design . The thin innor core is better than concrete but does not as much as one would think . On my concrete floors I put down 3/4" foam then 7/16th osb with a combination of glue down planks and carpet tile. I can peel up each individual piece and replace if ever needed. Glue down will also follow slight rolls in the floor and is easier to install. Best advice my flooring contrator ever gave me and is all he will ise now as well. The stuff I use also has a 20 year commercial warranty. I used Lifeproof once and never again , it was pain in the ass to install and 1 call back could kill any profit margin.

Vinyl does expand and contract significantly due to changes in temperature. WPC floors contain some air in the core, which obviously expands and contracts with temperature changes also. But vinyl is only one component of these floors, actually a small part by weight. WPC floors expand and contract more than SPC floors.

Sunlight shining on a floor will increase the temperature of any floor. The amount of temperature increase is partly dependent upon the color. Very light colored floors will reflect most of the light. They will not get really hot like a very dark floor. The temperature increase is partly dependent on the length of time it’s exposed to the sunlight, the season of the year, and the time of day. The latter two affect the intensity of the light.

That said, I would not install medium or dark colored WPC flooring in an area that received more than 15 minutes of direct sunlight around noon in the summer, in an air conditioned house. Perhaps 25 minutes around noon in the winter. In the case of most WPC floors, if you can keep the temp of all parts of the floor (not the air in the house) between 60 F and 100 F (a spread of 40) at all times, you probably won’t have any problems. This is also relevant if you have a fireplace or wood burning stove that radiates heat.

I suspect that a dark SPC or WPC floor, in an air conditioned house in the southwestern part of the U.S., exposed to direct sunlight in early afternoon for a few hours in the summer, would probably reach a temp above 145 F on many days. That would be more than a WPC floor can stand. I doubt that an SPC floor could handle 145 F on one part of the floor and 75 F on another part (a spread of 70) without any problems.

COREtec guidelines for WPC products state that “the post installation temperature range allowed is an ambient room temperature between 32°F and 100°F).... Avoid exposure to direct sunlight for prolonged periods, doing so may result in discoloration. During peak sunlight hours, the use of drapes or blinds is recommended. Excess temperature due to direct sunlight can result in thermal expansion and UV fading.”

SUPERCore Xtreme, an SPC product, claims that it is “dimensionally stable from -30° F up to 155° F”. Personally I think that’s a stretch. If part of a floor is in the sun at 155 F and part is 75 F (a spread of 80), I think you’ll have problems with the floor buckling and becoming wavy. Some click lock joints would probably fail. On the other hand, if the entire floor of a cabin with no HVAC went from 30 to 110 slowly over several months, it may not pose a problem. I don't know for sure. Just a reasoned guess based on some experience and knowledge of these matters.

Perhaps WeShipFloors.com, the vendor of SUPERCore Xtreme could weigh in on this issue. I wonder if they’ve received any complaints about floor failure due to excessive sunlight, from people living in the southwest, where the sunlight is really intense compared to the rest of the country.