Is the load in my attic play area ok?

Can I make a play space in the attic for the kids, is load an issue?
I have a traditional built stone house 85 years old with a steep pitch welsh slate over sarking board roof at 50 degrees. The trusses were built on site, rough sawn 5” x 2” for both rafters and joists. The loft space is 10 metres x 4 metres.
I am converting it to a play room for my two kids, they will get two thirds of the room and one third will be for storage because of where the loft ladder hatch comes in.
I have added hanging posts to all trusses 120mm x 45mm C16 nailed and then single bolted M10 top and bottom. The finished room space width is 2.3 metres. It’s never going to be a room from a surveyors point of view as I can only stand in the middle but is more than acceptable for scaletrix etc!
Two of the trusses are directly on top of load bearing studs below. The rest are sitting on a wall plate on top of the stone outer walls.
I have put down prefinished pine flooring from Wickes 21mm, I’m very impressed with it. I was going to timber clad the walls and inlays with 14mm T&G but when considering paint cost, time hassle etc it is actually cheaper to use the prefinished flooring on the walls. Ive done one gable end with the 10% spare I ordered for the floor and it looks great.
My concern is weight. I will be using 500kg of the 21mm flooring to do floor, walls ceiling, gables etc.
Does anyone have a ready reckoner I could use to work out how acceptable this is? By adding the hanging posts nailed and bolted and tying everything in with the structural flooring timber which I have screwed with SPAX flooring screws I think it’s all very strong and beefed up. There will only ever be some toys, a TV, bean bags etc for the kids and some suitcases winter/summer clothes etc in the storage end. I’m just a bit overkill with safety and its starting to play on my mind.
Cheers

Your concern should also be fire. Are you doing any of this through Building Control? One assumes not if you only have a ladder ......

No im not doing it through building control. A stair would ruin the room it would come off and the attic is not tall enough to warrant a full time room conversion. So your saying from a technical point of view no stair = no play room? Ive had a keen interest in houses in my short life (40) and ive seen several finished loft rooms with ceiling heights and ladder/steep stairs that are not classed as rooms from a home survey report point of view. Id be surprised if this wasnt a relatively normal project done in the UK to give kids a 'den' etc.

Glenbirnie said:

I’m just a bit overkill with safety and its starting to play on my mind.

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Except where fire is concerned. Oh well, house fires only happen to other people.

When calculating ( estimating ) the load do not forget that a child jumping up and down on the floor exerts dynamic loading which can be three times it static weight

You can put a brick on a glass table and it will not shatter, drop the same brick onto the same table and it is likely to shatter

Freddy Mercury

Forums are funny you get two types of people, those who offer the advice and recomendations and those who say you cant do that at every opportunity! You actually havent offered any decent advice at all. Youve just said youve not gone through building control so you cant do anything. You could close this site down and just make the front page say 'call building control'. Any one doing plumbing, call a plumber, anyone doing electrics call a sparky. By all means offer 'advice' but attacking negatively doesnt help anyone.

Anyway Ive decided to sell up as the whole house is nearly a 100 years old and far from being up to standard building regs, theres lead pipes and paint all over the place, think ill camp in the garden tonight. Right heres a question for you. My tent has a floor width of 4 metres and a 55 degree pitch, ive fitted hanging posts allong its length so the usable floor width is 2.3 metres. Do you have any ready reckoners that I can use to work out the truss strength, Im concerned about snow loading!

No problems, a roof pitch of 55° will ensure any snow will not be able to settle and build up.

Timber unless rotten or riddled with woodworm, bends a lot before it breaks. The structural designs are for joists which do not bend very much so do not crack plaster ceilings or rattle light fittings. if you are OK with risking this.. . . One thing you have not mentioned is insulation, its worth doing as the play room is more likely to be used when its cold outside. My barn has a limestone flag roof and I calculated that the slabs weigh about 4 tons (8m X 5m total coverage) so the roof can be ignored, how ever the dynamic load of a child jumping and landing on their heels could be a problem.
I have seen some unofficial "loft conversions" and the structural side seems to be not a problem, though the fire risk is. As a foot note, Children sleep through fire alarms so YOU will have to evacuate the building.
Frank

You can't expect people on this forum to offer advice on things such as structural matters, when the basic issue is fire safety.
As above, the loft won't collapse under the loading of the kids jumping up and down (though plaster might crack) but hanging
over it all like the Sword of Damoclese is death by fire.
Being concerned over anything else is like polishing turds.

To be clear this is simply a flat space for the boys to leave a jigsaw, lego, farm etc set up for the following weekend. There is no way they will ever sleep up there. It will be used on weekends and parents will always be in the house. It has a smoke alarm and carbon monoxide detector and a shallow angled fixed ladder. As for insulation it's been done with sheep's wool for the benefits of the timber as well as my lungs on installation. Fortunately it turns out the wife knows an architect so we're getting the loading formally checked but we've already been told there is no issue. As for should a loft be used as a play room I suppose that's up to the parents and there are a lot more considerations before you shoot someone down. I often study in the room the play room ladder is off for example I won't be getting ****ed out in the garden shed!