I am putting down some linear drainage at the edge of my drive that I am redoing. I am putting (50mm thick) blocks either side of the linear drainage (aco hexdrain), which will act as the edging to yet undecided finish (tarmac or blocks).
I am happy following the instructions on the web site bedding the linear on a dry C20 mix, haunching with a class II mortar. Then the two rows of blocks bedded on a full mortar bed (again C20). My concern is that if I end up laying blocks for the main drive, where does the haunching and hence the support from the lateral force of the blocks comes from.
I can only put it on the otherside to linear drainage, hence the lateral force would have to be transferred through the linear drainage, if the grate is removed from the linear drainage it seems not to provide any lateral support.
Can someone alleviate my probably unfounded fears, or advise how I should be doing it stop the problem?
I can't see anything wrong with what you are proposing - the linear drain with it's grating on is strong. I take it this is a resin based drain with metal grates?
RW Gale Ltd - Civils & Surfacing Contractors based in Somerset
to answer your question, No, because it is at the edge and therefore not driven on, I opted for the black plastic base and plastic grating, is this where I have gone wrong! :p
In my opinion, if the drain is to take any lateral forces, especially if it is at the foot of a downhill facing block-paved driveway, needs to be of a resinous construction to carry the loadings, irrespective of if it is trafficked on or not.
Can you return the plastic stuff and exchange for the 100mm Aco type resin made stuff?
RW Gale Ltd - Civils & Surfacing Contractors based in Somerset
The linear channel itself, whether it's plastic polymer-comcrete or anything else, is NOT the load-bearing component of such a construction: it's the concrete bed and haunch which provides that service. The channel is merely a smooth "liner" designed to conduct water away and to provide a fitting for the grating.
So, the channel should be laid onto a bed of 100-150mm ST4 concrete and haunched with same. A typical construction would have the edge blocks (those adjacent to the channel) laid directly onto the fresh haunching concrete.
It must be your lucky day beacuse I'm working on a linear channel cross-section drawing at the moment and I've adapted it slightly to show CBPs on the left hand side and mac on the right. Note the 150mm concrete bed and haunch, with more haunching underneath the CBP edge course to accommodate a full block, and also note how the paving should be 6mm higher than the channel.
Thanks for alleviating my fears Tony, putting the blocks and linear down on the same concrete at the same time was when I started thinking about the lateral support, never mind the hard work of trying to get everything level and down at once! :p
Managed to get 5 linear meters down on the Saturday, with the blocks on either side of the linear, I was using a dryish mix for the mass concrete to stop the linear drains floating, I walked over them today to see if any were loose, out of the 75 blocks I laid, using the same mixes and methods, 6 are now loose (i.e. removable) , these were fitted early in the day. Can anyone offer a clue as to what I did wrong? What I can do to rectify it? Do I need to apply this rectification to all the blocks or just those that are loose? Is a photo needed?
, these were fitted early in the day. Can anyone offer a clue as to what I did wrong? What I can do to rectify it? Do I need to apply this rectification to all the blocks or just those that are loose? Is a photo needed?