Wood Fiber Flooring Underlayment, 3mm (1/8 Inch) Thickness - 90 Sq Ft, Natural Soundproofing Insulation, for Laminate, Vinyl, LVT, LVP, or Hardwood

I was about to lay 3/8" Engineered Hardwood (Flooret Silvan) directly over tile, considered the Steico product and wondering whether I would need to pre-fill the grout lines (~1/4" wide by 1mm deep - tile is 20 x 20).Sunco (whose support has been fantastic!) of course gave a, honestly not unexpected reply, that their std recommendation would be filling the grout lines (not unreasonable). But while not endorsing per se, they had knowledge of users who had not and it appeared to be working out.I decided to go for it and have done a double layer (staggered pattern) over a 1/8" lower tile level and single level 1/8" (3mm) over the main area tile as per the image above.I did a test - with the 3mm product (only, no plank yet) I aggressively pounded /stamped / jumped/ beat on it above the grout lines and could NOT get them to telegraph even to the bottom side let alone through to the top!So I may get some disagreement from the community here on pre-filling but with my test and the fact that the engineered wood flooring in itself is quite rigid, I had no qualms about going straight over as-is.Image shows an area that had a tile field that was exactly 1/8" below the main tile level: I believe house originally had carpet section there and previous owners filled with a different tile, but not fully flush up to the other tile.So for this section I put one layer of 3mm in to exactly fill that section to its perimeter with the other tile, then a complete layer of additional 3mm over everything. I was careful to stagger the joints so they did not overlap between first and second Steico layers, nor the planking joints. (for the plank it's easy - fraction over 7" wide which is not a factor of 24 or 36, so it will naturally not create any joints over underlayment seams.)It is SUPER easy to work - cuts easily. I personally found scissors a better tool than a Blade.And I wondered if it would be more work than 'roll' type underlay which I have used previously. Actually I found it to be convenient - one row of 2' panels would accommodate 3 rows of plank and I could just lay as much underlayment as I chose to work my way across room (while juggling furniture around)The result underfoot is that it feels great - indeed quiet and comfortable, and that is also borne out when witnessing from level below.I am absolutely delighted by this product and would not hesitate to recommend this product to anyone.

I put STEICO wood fiber underlayment (6mm) under my new hardwood floors, and honestly, I’m super happy with it. It’s all natural—no plastic or weird chemicals—which feels awesome for my place and the planet. Laying it down was a piece of cake; the sheets are easy to handle, and I just sliced them with a utility knife to fit.It’s crazy how quiet everything is now—footsteps don’t echo, and the whole room feels chill. Plus, it handled some uneven spots on my subfloor like a champ, and the floor’s rock-solid—no creaks or bouncy vibes. A few months in, it’s still perfect. If you want something green that actually works, STEICO’s legit!

We removed 3/4" hardwood and replaced with1/4" LVP. This 1/4" Steico product was a great alternative solution to laying 1/2 OSB or other 4x8 sheets of fiber board to level my floors.Easy to work with and yea it is very dusty but worth it in savings and also sound dampening.Tip: after cutting out the holes for floor vents, use duct tape around the inner edges of your floor vents and fold over the fiberboard to prevent any dust from the product being blown out when your hvac fan runs.All in all I saved a ton of money with this product and our door jams are now only 1/4 off what they would have been with LVP only.4 stars only because of the dust and slight skin irritation from running my bare arm across the boards.

Some reviews say not to use this for LVP (or LVT) but this stuff was fantastic for our finishing over the garage space. Builder did not insulate the garage ceiling as it was "just attic space" so we needed a better underlayment to help combat the lack of floor insulation.This stuff goes down EASY. We did buy underlayment tape, but it did not stick to this, maybe duct tape would have but it is too thick, so we ended up just laying it with no taping. It's easy to cut, and FIRM on the wood/plywood subfloor (it actually added to the firmness for the LVP).Helps greatly with air/heat containment and the floor (only 3mm thick stuff) feels like it's much thicker - it was like upgrading the LVP to 8mm stuff! Super-smooth laying the LVP on top & floor feels amazing & looks like a pro did it (not us DIY-ers!).TIP: use gloves! This stuff is 'wood fiber' and without gloves you'll have tiny little wood fibers ( we had to shake out clothing & wash it twice after using, so we learned quick to be 'careful' while handling it!).

Overall, this is a decent product. It helps capture moisture and is a great price. I thought it would be thicker, and wished it was slightly thicker. I like that it is sustainable. It is easy to cut. However, when using it, green fibers were everywhere and irritated our throats. Some boards were also mildly with black spots, which we did not like. It is flat, but the texture is soft and we wanted harder. Overall, it is a decent product for our budget and did the trick.