Black Mark/Dust along the Edge of Carpet

Hardboard will have zero effect on the marks, it is known as up draft and very hard to stop if you have it, ask your carpet supplier to fit a good quality paper felt before fitting the new underlay, they must remove the old gripper to and fit the paper tight against the skirtings, use a sealant to fill the gap under the skirting, but not so much as to prevent the carpet being tucked behind the new gripper, the paper must be overlapped and taped, the new underlay must have the joins taped and the fitter must keep the spikes dialled up on his knee kicker so as not to pierce the underlay or paper, then fingers crossed it work, but hardboard is just a complete waste of your money

Hello, yes I would say that your builder is talking sense. Obviously the sub floor ventilation is good and dust is blowing up from underneath & making its way through gaps in the floorboard.

If you’re talking about black marks around the perimeter of the carpet this is probably coming from the Skirting boards, if this is the case you should follow these steps: 1) Hoover or sweep under the floorboards until dust free. 2) go over where you’ve just hoovered or swept with a sponge with warm water 3) once dry use a decent grade silicone sealant to seal the gap under the Skirting. 4) if you’re getting dust coming up from the floor boards you should use paper Felt between the subfloor and the under/carpet. Rgds

It’s definitely dust coming up through the floorboards, hardboard sheets fitted tight to skirting to leave no gaps is the perfect solution

normally when you have the black marks around the edge of the room and under the door this is the air flow going across the carpet and when the dust in the air hits the skirting board or the door the dust will settle and form a black line if the black mark comes from under the floor boards usually you will have black marks across the carpet in line to follows the gap in the floorboards it only normally shows up on light beige or cream carpets

Hi.......hardboard CAN be used, but nowadays we use 5.5 / 6 mm ply.If this is fitted, stapled professionally by a floorlayer, (100 MM CENTRES),then the joins, gaps & against skirtings `feather finished`, (with skirtings sealed beneath with caulk or silicone if raised), your problem should go.Have done this quite a few times, without fail, Hope this helps, Chris M-W.