Don't want my greenhouse blowing down..

Excuse me sir..yes you..I'm talking to you - the chap with the greenhouse, flatcap and fishermans jacket bursting with handy little tools poking out...your advice is much needed.

Im a idiot. There I've said it. An idiot with drills, hammers..manly stuff..but, like all men, I do have a

I have a 6ft x 10ft greenhouse - yet to be erected. I have a concrete base. I want to lay two high ( flat ) breezeblocks and sit my greenhouse on top of this. I want to do this for two reasons, (a) my concrete base isnt level..hopefully my breezeblock wall will be! and (b) height. I always recall my grandads, hitting his head on the grape vines which ran everywhere/tied to every rafter..

My question(s), I have the greenhouse base. How do I secure this base to my breezeblock wall?

It seems to come with some poles which ideally I'd cement into the ground. Obviously I cant really do this do i simply..drill holes in the base willy nilly..and raw plug it too my breezeblock wall? Use concrete screws?  Your advice is needed please!!

I suppose I dont even need the base..but then..seeing as I have it..and it would give me a fraction more height. I weakening my structure by using the base..on a breezeblock wall?

Finally, the breezeblocks themselves...assuming they need to be a certain type. I know they crumble easy!...

Any any men! out there ( women too ) with any answers to these little questions would be muchly welcome.

Thanks for your time, appreciate any replies.



  • BobTheGardenerBobTheGardener LeicsPosts: 6,499

    Hi garjobo, while I don't really fit the description very well image, I am pretty handy at DIY and will try and help.  First, breeze blocks come in 3 types, low density (sometimes called aerated), medium density and high density (sometimes called concrete blocks.)  You want medium or high density.  Medium density can be drilled fairly easily and are strong enough to take rawlplugs.  High density will be much harder to drill and are much heavier.  Don't use low density - those are the crumbly ones.

    First, lay your base out on the concrete and make sure it is square by measuring between opposite corners.  When both measurements are exactly the same, it is square (ie all corners are 90 degrees.)  Lay the base on the concrete slab (which you say you have already laid) and, using chalk, draw all the way around the inside of the base.  Using a straight piece of timber, mark another line about an inch inside the lines you drew on the concrete before, so you end up with two rectangles, one inside the other.  Lay the breeze blocks to the inner lines using a 3:1 mix of builders sand and cement, so there will be one inch of breeze block showing all the way around the inside, when you lay the base on them. This gives you some leeway and will ensure that the rawlplug holes (which you will drill later) aren't too near the edge of the blocks.  Wait a few days to make sure the cement has set (cover with plastic if rain or frost is expected.)

    Drill 5mm holes through the bottom of the metal base (about 4 or 5 holes along each side will be enough, and 2 or 3 at each end) then lay the base on the breeze blocks and mark the breeze blocks below through the holes (eg using a permanent marker pen.)  Remove the base and drill holes for the rawlplugs at the marks, using the correct size drill bit to suit the rawlplugs (I suggest 6mm rawlplugs.) The holes need to be 45mm deep (wrap some electrical tape around your masonry drill bit, so there is 45mm of bit showing from the tip, so you don't drill the holes too deep.)  Screw the base into the rawlplugs using size 5x45mm stainless steels woodscrews (eg 5x45mm turbo ultra from Screwfix.) It is important to use stainless steel screws when fixing aluminium anywhere which will get wet as even zinc plated steel screws will rust quickly.  If any of the holes are in the wrong place, you can still unscrew the base at this stage and drill new holes.

    Hope that helps!


    A trowel in the hand is worth a thousand lost under a bush.
  • garjobogarjobo Posts: 86

    Bobthegardener THANKS for your time/trouble replying to this. I will definately take this on board and follow it too the letter. Your reply is better than the greenhouse instructions I have!

    Whilst have you final thing. I intend to make things a little difficult for myself - again I am a man afterall!! - once this greenhouse is on the breezeblocks I intend not to have a step in / out. Instead...i intend to cut the base /  build the wall with a gap. So..basically the sliding door only needs to be extended so i can walk in / out with ease.

    I know some of the problems I may have..aka, the slider at the bottom and extending the door itself. But do you think this is not really much of an issue..and do-able.

    Surely, all im doing is..sticking the slider / or buy another make-shift one - and stick it at the bottom of the wall..and then simply extend ( bolt aluminum pieces ) onto my existing door. Wouldnt be extending by much ( two flat breezeblocks worth and a base I suppose ).

    I know..a lot of effort/time/money for simply a short wall..but..well...its in my head..and im going to do it. Your thought welcome...just any problems you see I might come across. Intend to do this project - right -.


  • BobTheGardenerBobTheGardener LeicsPosts: 6,499

    The sliding door extension might work.  Most of the weight of sliding doors is taken by the top rail (there are usually wheels in the top of the door which run along the top door rail which comes with the kits.)  All the bottom door rail does is guide the door and stops it swinging outwards, so you could even screw a piece of timber to the concrete to do that.

    I would build the base and greenhouse as it is first (but no glass yet), so you can see how everything works, then cut parts out to extend the door later (an angle grinder with a metal cutting disk will easily cut through both aluminium and breeze block.)  One problem may be that an extended door will hit the breeze blocks when you slide it.  The way around that might be to set the the breeze blocks on that side of the door frame in a different way, so they are flush with the outside, or cut part of them away with a chisel.  The most important thing is that the greenhouse frame and base is supported from below by the breeze blocks all the way around where there is glass above.  If you don't do that, the weight of the glass will cause the frame/base to bend and the glass will crack.  If you can't see an easy way to do that on the door end, having to use a couple of steps wouldn't be the end of the world! image

    A trowel in the hand is worth a thousand lost under a bush.
  • FairygirlFairygirl Posts: 19,762

    Garjobo-can't offer any advice -Bob's got it nailed anyway!- but your post really made me laugh-brilliant!image

    to walk through a forest is to touch the past

  • garjobogarjobo Posts: 86

    Fairygirl - i figured it was one way to get a reply to this thread and it worked! Bob really has helped - my plan will be put into practice shortly. Glad to read Bob about weight of door. Flicking through greenhouse instructions ( they really are bad ) i see there is a wall for the slider etc.. all sorted. I think I will film/photo part of its construction and youtube it or something. Disappointed looking on youtube at others efforts..would of thought be more examples of a greenhouse on bricks etc

    Anyway thanks again. I will indeed build greenhouse, and cut the al. frame once complete.

  • Andy19Andy19 Posts: 549

    I know someone who done this the way bob is telling you and he extended his door by screwing those thick clear plastic 6inch strips you see on big freezer doors to kept the wind and rain out it does the job well. Also instead of glass you can put polycarbonate in the door not as heavy and cant really break hope this helps you.

  • figratfigrat Posts: 1,619

    Hi garjobo!

    No advice whatsoever to give, but I admire your tenacity and think that Andy's idea of the heavy duty freezer strips is inspired.

    Am really looking forward to seeing pics of the finished item.

  • dannyboy10dannyboy10 Posts: 127

    I agree with bob and my green house was put up this way,I also added concrete to all corners of the base when the greenhouse was fitted.


    Like bob says measure corner to corner it all should be the same size if it is not you will have problems fitting the glass

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