Every good structure is preceded by a good solid base or foundation. When it came to choosing a material to use as the greenhouse base, it was obvious that paving slabs would be the best choice. Due to the location and nature of the build, paving slabs will be the quickest and most convenient method for us to use, while still providing us with a semi permanent solid foundation. If I had been building the greenhouse on my own land I would bed the slabs on concrete, but as I will be growing vegetables within the vicinity, and because I may want to move the greenhouse in the future (were only on our second full season), I decided to lay the slabs on a bed of quarry dust. When laid correctly, leveled and maintained, a well pointed paving slab area will provide a strong and weather proof base for many garden structures including shed bases, greenhouses bases or just a seating area.
Before I tell you how I laid the slabs there is a few important safety shout outs I must give.
First and foremost paving slabs are very heavy. Anything above a 2′ x 2′ paving slab is a 2 man lift. Gloves and steel toe cap boots are essential and if you need to cut the slabs, then you will need eye protection, ear defenders and a dust mask. When it comes to cutting slabs, the only viable method is to use an angle grinder/ Stihl saw with a concrete cutting or diamond tipped blade. If you are not confident or 100% competent, using either of these tools then you are better leaving it to someone who is. These are very dangerous tools if used incorrectly or in the wrong hands.
Tools you will need for the job.
- Spade – for digging down to level the ground, also helpful to open the bags and spread the quarry dust.
- Rubber Mallet – This is good for compressing the slabs into the bed of dust and to level off corners without damaging the face of the slab.
- Spirit Level – This is essential to level off the dust to get a consistent level plane, to lay the slabs on. It is also a good tool to drag the dust back, and to use as a tamper to even out the dust.
When it comes to leveling the dust off, I use the edge of a large spirit level and level each side first to a desired height. This means that as long as either side is level, I just need to keep the dust up and flush with the bottom of the spirit level.
Its important to remember when laying a slab beside another slab, not to get your finger trapped between both edges. When the slabs are laid firmly on the dust you should be able to walk on them, without the slabs rocking back and forth. If you need to open or adjust the spacing’s simply stand on the slab you don’t want to move and use a spade to lever the opposite slab into position.
I am still trying to decide what I am going to do about the spacing’s. The obvious option is to use concrete and point them, but im trying my best to refrain from using any concrete products on my plot. If you have any suggestions of what I should use, please send me an email or contact us on Facebook.