Hi,there,new chap in the house just joined up,i run a high pressure cleaning business down here in sussex been going a few yrs now and have gained a lot of experience during this time,and one of the biggest pains is cleaning decking,tbh i sometimes price it so high i dont really want it,but if you dont mind i'd like to share a few tips with you.
1st of all you say its been painted,ask yourself what type of paint(oil or water based)if its oil based then you may stand a good chance of getting it off,BUT and i mean BUT,theres a lot of problems your'll come across 1 of em is the stripper,for most paint removal and finding a good one is its cost i use paramose FS10 you can only get it in 20lt tubs and that'll set you back £120 it is lethal in its form but does break down with water and is bio friendly you need to read the fact sheet on it then again theres other stuff but i wont bore you with them.
With water/acrylic based paint you've more work on your hands because this penitrates the wood even more just like a stain and trust me your decking might look worse than it was before mainly because without getting the nozzel up close you run the risk of lifting the top fibers of the wood then my friend your in a world of hurt,this depends on the quality of the decking,pre-treated is different to pressure treated i'll let you do your own homework on that.
The other pain with paint on decking,look where the decking is,bet you any money 9 outa 10 its right slap bang near the lawn,think,all that loose paint stuck in the grass is a pain in the a**e to it get out best get your mower out with a grass collection box or a leaf vacume if it goes onto any hard surface ie slabs or concrete wash it away dont try and sweep it up it'll be like wet sand,impossible,your'll have to wait till its gone bone dry,like dust
With the actual cleaning useing a pressure washer couple of things you got to bear in mind,STRIPING you must keep that nozzel head the same even distance from the decking through out if you dont you'll get a different cleaning pattern and you may have to go over it again when that happens light and dark areas of cleaning will happen this is so time consuming,of course you could go out and buy yourself a flat surface cleaning if shes willing to pay for one(£100-£700) but you still end up using a fan nozzel to get the places this wont do,ie the edges,and whatever you do DONT USE A TURBO NOZZEL,you'll rip the top of the decking to bits
OK,to sum up for paint your'll need a good stripper,low pressure but useing hot water,bit of discipline take your time,as for stained decking forget it it'll never go back to what it was like the day it was layed
After all this see if she'd like to have it a painted in a different color where all you need to do is clean off the dirt/grime/moss and recoat never know that price might work out better with less agro to
Blimey,1st post and i've gone on abit,anyway hope this helps you Andy and others
chris