Theres a system for building sets which means to an extent you can recycle a lot of material from one job to the next so they can get recycled to a certain extent, props tend to be hired as much as bought / made so there a few big warehouses around the country full of props and furniture.

Also have you made any stuff we might have seen on TV

The 'most-seen' thing I've done is this probably this train :-)

https://www.youtube.com/watch?v=Yh2yZf8F-60

In my spare time I sew power kites (anything up 5metres, or what can go through my sewing machine!) ,Ive also been making a wind breaker awning(just a one 1metre by 1.2m wall, no roof) from Ripstop nylon which is flame retardant as neighbours have bbqs and I wanted a little more safety as there would be possible sources of ignition from sparks which led me to more reading. Unfortuantley here in the Faroe Islands , when its bbq weather there is always a cold northerly breeze , I will never complain about bbq weather in the UK when I visit !

However with the teepee I think its best with the untreated canvas, you learn something new everyday !

Your profession sounds really interesting , I've always wondered what happens to all the bespoke set material and props that you have make after shooting has finished , does it get sold ?

Also have you made any stuff we might have seen on TV :D ?

very little what - your house is full of lots of things. Certain regulated things like furnishings and upholstery should be flame retardant - furnishings yes, kids clothes - yes. Your clothes, kids toys*, other general possessions very definitely no. I build replicas of houses and interiors for film and TV and one of the obstacles to doing that is most of the stuff you build and furnish your house with isn't considered safe enough to take into a television studio.

* the scare in the last few years with kids fancy dress costumes - particularly haloween costumes - catching fire is because the manufacturers / retailers classed them as toys rather than clothes and as a result applied laxer standards.

I spent a day blowing up sections of aircraft fuselage once (long story). Set up - bang - pick up the pieces... repeat. Each blast was a mixture of air frame, seat, flooring and fixtures (overhead lockers etc)

For the last blast we also included a quantity of packed luggage - bags, suitcases, clothes, toiletries, toys etc.

Set up- bang - massive inferno. The luggage was hugely and persistently inflammable - not just burning but sticky like napalm and black noxious smoke. Wasn't really a result we were expecting to be honest but quite sobering to see that the most dangerous material in a plane would be the stuff I was wearing and carrying. The bags and cases were especially fierce when burning.

From my own experience too - being inside a fleece jacket when it catches fire and both melts ands shrinks as it burns is quite alarming.

For the OP making tents - you're right at least choosing cotton / canvas over something man-made - at least it doesn't melt or create toxic fumes. You'll find that any material of that nature sold as 'flame retardant' the treatment is non-durable ( marked NDFR ) which means it won't retain that quality if it gets washed. You can buy little spray bottles of the treatment though - such as Flamebar or FlameCheck from theatrical chandlers (Flints, Russel and Chapple etc.) Those suppliers will also sell various safe to use fabrics and clearly mark whether they are inherently flame retardant of have a non-durable treatment

We used to have a plastic one for outside and an old quilt with bean poles for inside.... I understand the fire safety concerns but is everything in your house flame retardant? the distinction to make is whether you can drop it and run away if it catches fire - this was the issue with costumes being classed as toys - you can drop your teddy you can't as easily drop your princess outfit. So with a tent / play structure / den the problem is you're inside it

If its safe then the only lights will be LED fairy lights. Definitely no candle based ones

My advice is.

put the tea lights the bin unlit jams jars to reduce fire risk.

Most hateful things.

And I read some articles in peer reviewed journals , so I thought I'd ask on here.

Just kidding, thx for reply