Old greenhouse structural problem

Hello all,
My aluminium greenhouse has started to show its age. I have quite a bit of pitting, mostly on the inside on/ in the Aluminium extrusions. Some parts are worse than others. The roof seems the most in need of attention. It is still structurally sound. Is there a fix for this.
Any ideas welcome.

 

Hi,

They all seems to go like that after 10 or 20 years, just its nautual patina as some would say.

Thought not tried it yet, a carefull test of light sanding with some very fine emery or wet and dry paper or wire wool should restore the surface, even some liquid metal polishes or pan scrubbers may work ok.
Avoid any strong wire brushes etc as they will put deep marks into the surface

Again not tried, but a possiblity, is to give the frame a clean and then use a suitable paint of your choice, one that will withstand the moisture and last for many years.

Often just removing the glass and giving the whole frame and wash will make it look refeshed as the moss etc can really collect where the glass meet the frame.

 

I think it's just the way aluminium oxidizes, if you spend lots of time cleaning it up it will go dull looking again pretty fast.

 

Just tried a few things on ours and you can remove the markings, but it would take hours,days, weeks to do a whole greenhouse ! and as said by @pete because the surface is now more 'open' due to the abrasive cleaning it will likely show and dirt and marks up quicker.

Other than just washing any dirt off it, think the only practical way would be a new one.

Be interesting to hear if the factory painted types remain good and perfect for at least 15-20 years. Expect they could look shabbier if the paint bubbles off in a few years or is damaged etc.

 

Not sure but I think you need special primer for aluminium, so painting it by hand could be a bit of a disaster as Ricky says.
I assume the ones that come already painted have a factory finish which is more resilient.

 

I think are lot of the coloured greenhouses are powder coated rather than painted.

 

Any idea how long that finish lasts in a typical garden ?

 

The thing with aluminium is that the outer oxide coating actually protects the rest of the metal from corroding. It's not like steel - steel is actually one of the few metals where oxide does promote accelerated corrosion. So I think you don't need to worry too much about this.

 

It is old, the store I bought it from was Maidleys or something like that. I believe he was a footballer. It has to be 25 + years old. I did try a little car polish and this did help a little. The polish must be very old as well I cant remember the last time polished a car. Turtlewax. Probably collectable. Reading all your replies I do agree that there is no turning the clock back. I may just leave well alone as it is not a serious condition and probably will remain structurally sound for many years. Whatever is on there may help protect whats underneath soapy water may improve things visually.
Thanks for replies they were helpful.

 

Cut & pasted from the net.

1. Use a soft cloth to remove oil and surface dirt with any suitable mild cleaner such as dishwashing liquid. Do not use steel wool, steel wire brushes, or sandpaper.
2. Hand polish the corroded area with metal polish (Brasso is one such brand).
3. Rub over the polished surfaces with a soft cloth and wax polish.

 

I will have a go after the Toms and peppers have finished. Its a nice job on a wet miserable day, end of Sept October time. It always has a good clean before winter and another in early spring. I will look into the Alloy this time, but nothing invasive, just a wash and polish seems the way to go.

 

Rhino give a 25 year guarantee on their coloured finish For an 8*8ft greenhouse powder coating is an extra £450.
@hans My 20year old greenhouse aluminium looks very similar to yours. Aluminium doesn't really corrode. The oxide layer protects the underlying aluminium from corrosion. Salt solutions, sea water etc can cause pitting on aluminium and alkaline cleaning agents should be avoided as these can remove the oxide coating.

 

This greenhouse was bought for £50 many years ago. As going around the Garden section with my wife I said 'I wouldn't but a greenhouse from here as they are too dear'. The other side of some staging a local chap, working there, who I knew, said there is a nice one outside ex display, door not perfect but easy fix. The £50 sign had blown over. We paid for it, they dismantled and we collected it a few days later. Transit van job. The glass is fitted with screwed full length beads on rubber seals, the whole thing is well made the sliding door just needed the top and bottom rollers adjusting. Concrete was poured with a 'soil window' for a Peach tree and a black grape later.
So all in all a excellent purchase.

 

Hi

I have not read all of the above in case it has already been said.

Its just the way aluminium oxidizes and degrades over time, there is nothing you can do really even the expensive ones covered in plastic will blow up after a while where the moisture gets underneath from condensation.
The best one I ever had was made from proper double glazed upvc window units, mis-measures put together from a double glazing company.