we have been asked to lay a large area of Marshalls concrete block paving, 80mm square tegula cobbles.
It is to be laid on a concrete slab (underground carpark below)
This slab will be tanked and a 25mm tray laid on top (similar to what is used in tanking basements i believe )so what water that makes it through the paving is channelled towards the drains.
If we were to lay our paving directly on top, the built up of sharp sand will vary from 35mm to 100mm to get the falls required.
Should i screed it in a sharp sand cement mix ?
any suggestions much appreciated
I was interested in this topic, but I think the answer was really recommending solid base rather than flexible due to the variation in depth (35mm to 100mm).
If the depth of screed is reasonably uniform would you consider 50 to 70mm final compacted depth for a 50mm concrete block paving too deep (or too variable)?
What depth of partially compacted screed would be necessary to achieve a 60mm compacted screed? [How long is a piece of string - I hear? ].
I need somewhere to start, so if 30mm goes to 25mm and 50mm goes to 41mm, sounds like I need to test at 75mm partially compacted screed and compact to ca. 61mm. Is this depth of pre and post compaction screed excessive?
Many thanks
De1b0y
for a flexible base anything over 50mm is asking for trouble
solid need to be 100mm ideally but if you are overlaying concrete you could go thinner
cheers LLL
Many thanks.
Sounds like I need to go thinner on my screed base.
If I aim for your advised maximum 50mm compacted screed [can't go lower due to kerb position], do you think 61/62mm partially compacted would give me a test starting point to get to 50mm fully compacted?
Much appreciate your help.
Regards
De1b0y
Many thanks to LLL and matt h.
I will keep as shallow a screed as I can; sounds as if I am on the limit with 50mm final compacted screed with 50mm blocks. I will also try LLL's double notched approach.
With this approach, can I confirm if after wacking at 40mm whether you scrape level again before adding further loose screed and scraping to 50mm, or just wack at 40mm and then apply loose screed and scrape to 50mm? [Does this question make sense??]
Thanks again
De1b0y
screed to 40 mm below finish,then wack
then screed at 50 mm lay blocks then the final wack
with 60mm blocks this works for me
LLL
ps i dont like 50 mm and wont use them
