Greenhouse Roof

GREENHOUSE ROOF CHANGE

A while ago I mentioned a problem with the vinyl vapour barrier I used as roofing.  The sun had taken it's toll and it was badly deteriorated and breaking apart.  Time for a replacement.  I had a few options running from doing it the same way as before, using the same inexpensive material, and in a few years facing another replacement.  Sounds like not too bad of an idea until one takes into consideration the extensive labour involved in trying to get the plastic sheeting in place with as few wrinkles as possible, and how awkward it is to put the strips of cedar lath to hold it down to the rafters.  And the price of cedar lath seems to have gone up a LOT since last time I used it.

At the other end of the scale, one could use acrylic panels which would have cost hundreds of $$$.  So, I searched around and to my dismay it turned out to be hard to find the corrugated panels in eight foot lengths.  

Finally found some at Home Depot for slightly over $20 each (including taxes) and it took 8 panels to cover the roof.  In addition, for about $15 I got a box of 50 screws with rubber washers to seal them to the roofing.  Add to that another $12 for a couple of lengths of vinyl drip edge flashing for the sides (over the door at one end, the window at the other).  I might as well mention that when I tried to find the vinyl drip edge it was not in the shelf stock.  It was on a big cart with other vinyl products - waiting to be "put into inventory".  So - I was informed by 2 different  people that they could NOT SELL IT TO ME as it had not been entered into inventory yet.  A little discussion with the manager and my 2 strips became available, she just had to make note of what the item was and then take care of inventory adjustment.

Generally, one uses strips of wood or plastic to lay under the corrugations to seal everything down nicely.  However, my 16' roof with 3 rows of hold down screws meant 48 feet of strips.  At Home Depot they only had plastic strips - 2 foot long, in a 6 pack... and to get enough for 48 feet would have cost about $85 with taxes.  Found some made of cedar at Home Hardware for about $34.

Not always a good idea to buy from two different places for material that has to match.  Seems the spacing of the corrugations on my panels was different than the strips... different manufacturer means different spacing.  And of course Home Hardware were out of the corrugated panels in 8' lengths.  So - the panels ended up being fastened down without the wood or plastic strips, and it looks like it is going to work just fine.

Now that the roofing is in place I have to say I am impressed with how much clearer it is than the vapour barrier I had used before.  Looks very nice!  Brighter sunlight coming in through the roof might make it a bit hotter inside but an open door during the day will take care of that.

The final tally?  Well, probably about $200... not counting the frustration and fuel running back and forth to find what I wanted.

As you can see in the picture below, it looks much better than the vapour barrier, is going to be longer lasting (I hope!), is clearer, and it went on much easier than the sheet plastic roll material.

I was lucky - didn't have to cut it to length as the roof was about 7 1/2 feet so it has about a 6" overhang, which is just fine.