basement clothesline installation

Make sure there's plenty of ventilation to remove the dampness.

Unless your joists are already dangerously weak, screwing into them will be fine. If they are marginal, the centre of the joist near the centre of the room is taking least load.

The dampness is the real killer here. I have a room with several lines in it, albeit on the first floor, but when a lot of washing is to dry there a heater and a ventilator are needed or mould starts to grow on walls and windows frames very quickly. Brian

Bad idea. Basements are humid anyway, adding to it could start rot etc in your floors. Stuff would only dry very slowly anyway.

Agreed. Good through ventilation to carry away the moisture, or at least a good dehumidifier. Otherwise nothing will dry, and condensation, mould and possibly rot will proliferate.

Agreed also. The underside centre of a beam has the highest stress. Which is why (IIRC) in many structures, such beams are made thickest at the centres, reducing down towards the ends.

Double plus 1. A basement is probably already rather damp and cold so might not be the best place for drying clothes anyway.

If my 35 year old memory of applied maths and beam loading is correct the underside center span of a beam has most tension loading.

You can't weaken floor joists by suspending underpants from them - we are talking about a few kilos here, including the line, fixings and a full load of wet clothes

Don't do it, unless you have a dehumidifier next to it that you will have to empty regularly, in which case, having the line in the cellar is irrelevant as you could have it in any room in the house along with the dehumidifier

I was going to suggest a dehumidifier too. The merit of the basement is that you aren't cluttering up living space. The dehumidifier adds a bit of cheap warmth and will help to dry out the walls and floors too.

Thanks for all your replies! I appreciate it very much.

My grandma dried washing in her cellar for 30-odd years, and I have done so for 20-ish years. Perfectly fine as long as - as pointed out - there is adequate ventilation. Her and my cellars had residual heat from the central heating pipes running across the ceiling (under the ground floor). I wouldn't do it in a basement, though.

JGH