On Dec 2, 2:58*pm, "shazzbat"
wrote:
"Martin Brown" wrote in message

...



On 02/12/2010 11:03, aquachimp wrote:

The snow has exposed a curiosity. I took a photo, but it doesn't show
it adequately.

Where the snow had settled on the "new" area, the layer is thin.
Where the snow settled on the old area, it's noticeably thicker and
showing more signs of melting. That includes the areas of "old "patio
which I left intact to "frame" the new one, where the "old" was still
intact..

Anyone know why that might be.

I'll hazard a guess that the old stuff is higher density concrete slab
with a better heat conductivity and so very slightly warmer and sticky for
the snow when temperatures are sub zero for a prolonged time.

Thing to look for is next time it snows does the old stuff stay wet for
longer and then quickly build up whilst the new stuff still has loose
powder snow on it. My cast iron drain covers do something similar.

A similar thing has happened on our slabs in the garden this morning.
Instead of the snow over the joints being lower as I would have expected,
it's noticeably higher. Here's a pic, hope it shows up OK

http://i163.photobucket.com/albums/t...20stuff/02Dec0...

Steve

Having made individual "slabs", I then pointed them up using the same
strength mix, but no pigment.
There is no variation as shows up clearly on your photo. Indeed a
curiosity.

BTW, the snow on the "old" patio is also higher, but looks fluffier.
What is under the rather small and thin tiles (I wouldn't even call
them slabs) of the "old" patio is a thin-ish layer of splodges of
concrete, which is deteriorating and the remainder is sand for about
20cm and then the concrete slabs. (I originally thought I had found an
old patio under the current one.
I did not remove that slab layer.

So, to comment on martins guess, the _old_ patio is NOT a higher
density concrete slab.
But the addition of cement into the sand that was there, along with
the making of concrete slabs would, I think, make that a fairly
uniform higher density concrete slab (no splodges on sand, under thin
little tiles