Once all the roof glazing bars are out the ridge bar is the next. This is a simple job, two bolts only hold each end of the bar, these are untightened and then usually slide down the end extrusions allowing the bar to come away from the end sections. This is one operation where help is a bonus.
Once the roof is off you will be left with four walls bolted together. Every greenhouse is fitted to its base in its own way, this is the time to remove the greenhouse from the base. Once free from the base each corner of the house is generally held with three bolts, two at the top and one at the base.
The photo to the right shows a top corner section where on this particular greenhouse the bottom nut will untighten and the bolt can slide down away from the junction. The bar that the nut tightens over is the top bar of the side section. The top nut will require complete removal to allow the roof corner support bar to be removed before the bolt can be slid upwards and free of the junction. Once both bolts are away from the junction the side bar will simply slide out and the top of this section of the greenhouse will be free.
The bottom junction is dismantled exactly the same but there is only one bolt holding the bottom of the end section to the bottom of the side. At this point help is more than a bonus, you will now have a very unstable greenhouse flapping around. Carry on around the other three corners and you wll be left with four greenhouse sections looking a little like this.
This is as far as I go when I'm dismantling. I transport the greenhouse in four sections which makes reassembly a breeze. If you need to completely dismantle then I strongly recommend you make detailed notes of where each part goes, especially the ends. Keeping each section's parts separate will also help.
Rebuilding the greenhouse is basically the reverse of the dismantling procedure. The main point to remember though is that the glass is square, and will only fit into a square frame. Two things are critical when you rebuild, all four corners need to be 90 degrees, most people understand that. Where many fall down though is by not having a flat level base.
Your gutters will follow the base exactly, if you stand back and look side on at your gutters they need to be perfectly parallel. If they are not your greenhouse is twisted and I can guarantee that somewhere your glass will not fit properly. The only way this can be corrected is to lift the corner that is low, ideally by making the base true. If this is not possible you can pack the low corner and make good with concrete. Spend time and care on your base though and everything else will follow.
If you have found this useful please let me know, I love to hear from you and if you have found anything less easy to follow then I will try and rewrite it. I deal with greenhouses every day and I appreciate I may be assuming people know more than is the case. Finally if you need any nuts and bolts, glazing clips or glazing seal to rebuild your greenhouse I would really appreciate your business. If you're anywhere near East Yorkshire we are also cheaper than anyone else for glass, sadly we cannot post this though.
Good luck with your rebuild and happy growing, Ian isitt.