Just guess the hight. Then show us the aftermath on here.
Ladder?
Gun with grappling hook. Fire it into the top of the cabin with the tape measure attached then simply measure the height and guestimate the distance between where the hook penetrated the cabin to the top. I always add 10% on for accuracy and DO NOT REPORT THE HOLE IN THE CABIN TO MANAGEMENT, blame an agency driver. Simples 
FFS…this is why the industry is a shambles .
Dozy go become a postman !
Why do you do it to yourself really.
Soon as I saw thread title I thought oh no what’s he done now 
Easiest way Dozy is to chuck rope over from ground to ground, take away width and measure half of what you have left.
Serious answer Dozy, tie your tape measure to a line and throw it over so you can drag the tape measure up to where you want it.
Kaistar:
dozy:
How talls a portacabin now,I’ve tried to measure it with my tape measure but tape measure collapses before it gets to the top of the cabin,bloody Wilkoes tatGet on top and feed the tape down ? Play gravity at it’s own game
Sorry he can’t do that without fall arrest cable and an appropriate climbing device and dont forget the safety briefing 
+
= job sorted!
How did you get on then Dozy? Please do update us.
He has probably locked himself inside it.
the maoster:
01 += job sorted!
That will get Dozy the first 10" I reckon…after all he is a big prick !
Boom boom
3 wheeler:
That will get Dozy the first 10" I reckon…
Someone’s being optimistic … 
3 wheeler:
FFS…this is why the industry is a shambles .
Dozy go become a postman !
At least we won’t get any more bills or final demands in the post ! … or anything else come to think of it,
robroy:
martinviking:
, a ‘Plank’ .
I’m saying absolutely nothing.
My first thought too.
Toddy2:
3 wheeler:
FFS…this is why the industry is a shambles .
Dozy go become a postman !At least we won’t get any more bills or final demands in the post ! … or anything else come to think of it,
I like your thinking .
But
Is Dozy really a secret agent working for a a large European haulier, sent here to single handedly to bring uk haulage to its knees so the Foreigners can take over totally and then put the rates back up ?
2 days and no news. I’m getting worried for him now.
There’s been nothing on the Traffic news about portacabins wedged under bridges,…you don’t think he’s locked himself inside do you? or is stuck on the roof …I mean, this is dozy here. 
robroy:
:shock: 2 days and no news. I’m getting worried for him now.
There’s been nothing on the Traffic news about portacabins wedged under bridges,…you don’t think he’s locked himself inside do you? or is stuck on the roof …I mean, this is dozy here.
He’s still in the yard trying to figure out how to messure it
If the tape keeps collapsing just measure it half way then double the result… Easy