machtucker Posted April 16 Share Posted April 16 Hi everyone, Well the weather is looking to be better next week and I'm on leave so planning on doing a bit more landscaping in the garden. I'm going to excavate the bottom part of the garden (bounded by the yellow line in the model). There is a clay paver path to be laid on top of sharp sand bedding layer and also 6mm gravel in the other areas with a stabilisation layer and 10-15mm bedding layer of sharp sand. I'm planning to use a 100mm MOT Type 1 subbase layer for the whole lot. The question is should I put a fall on it or will it be OK level for drainage purposes? Many thanks, Ed Link to comment Share on other sites More sharing options...
ProDave Posted April 16 Share Posted April 16 Compacted MOT1 does not drain well, so don't expect water to drain through it quickly, so a fall would make great sense. 1 Link to comment Share on other sites More sharing options...
markc Posted April 16 Share Posted April 16 As above, Type1 holds water, if it’s under a drive or garden area, road plannings compact very well and drain well too. 1 Link to comment Share on other sites More sharing options...
saveasteading Posted April 16 Share Posted April 16 On 16/04/2024 at 14:33, markc said: road planings compact very well and drain well too. Expand They shouldn't if well mixed and compacted. A road is a mix of stones not unlike MOT I , but stuck together by a glue of bitumen. If it is supplied as all big stones then it will have gaps and drain. If it is footpath material or surface dressing, then it is weak but solid. I think the best of it goes back into new road surfacing these days, and the rest is sold off. On 16/04/2024 at 09:59, machtucker said: a clay paver path to be laid on top of sharp sand bedding layer Expand So its best to lay the base to a fall and try to keep the sharp sand depth consistent . And it will be easier to lay. 1 Link to comment Share on other sites More sharing options...
machtucker Posted April 17 Author Share Posted April 17 (edited) On 16/04/2024 at 14:58, saveasteading said: They shouldn't if well mixed and compacted. A road is a mix of stones not unlike MOT I , but stuck together by a glue of bitumen. If it is supplied as all big stones then it will have gaps and drain. If it is footpath material or surface dressing, then it is weak but solid. I think the best of it goes back into new road surfacing these days, and the rest is sold off. So its best to lay the base to a fall and try to keep the sharp sand depth consistent . And it will be easier to lay. Expand Yes that's how I will do it, just like I did with the patio. I was wondering whether I could get away without a fall though. I did read something on Paving Expert website that talked about a suds compliant solution which requires a different subbase with fewer fines. Edited April 17 by machtucker Link to comment Share on other sites More sharing options...
machtucker Posted April 17 Author Share Posted April 17 On this topic does anyone know where I can buy MOT Type 3 aggregate from? Doesn't appear to be as popular as Type 1 Link to comment Share on other sites More sharing options...
saveasteading Posted April 17 Share Posted April 17 On 17/04/2024 at 17:03, machtucker said: where I can buy MOT Type 3 aggregate Expand It is crushed stone without the fines. Type 3 is a particular grading and uncommon. You could get a lorry load more easily than a bag. A builders' merchant will have single size stone in big bags, with more or less variety according to local fashions. It can be expensive though when it is made from attractive stone for paths etc. I bought some last week called Cotswold stone (It is white and will be exposed) for £78 / bag whereas the sharp sand or gravel on the same delivery was £42. If there is a local stone then this should be cheaper. As it happens, it is for laying inside gravel grid specifically to be free draining. The original went in about 15 years ago and has had a lot of use. We are cleaning the messy top off and releveling some areas. Because of erosion it is not open textured any longer and it puddles locally where it has dropped. But because it is on a slope, any that doesn't make it downwards will run off because of the slope. Then it is caught in a perimeter layer of gravel and french drain.. To summarise. Single size stone or gravel is SUDS in itself as long a it is deep enough, to hold the rainfall, and contained . A slope is up to you, but where would you then catch any runoff? 1 Link to comment Share on other sites More sharing options...
machtucker Posted April 18 Author Share Posted April 18 On 17/04/2024 at 18:13, saveasteading said: It is crushed stone without the fines. Type 3 is a particular grading and uncommon. You could get a lorry load more easily than a bag. A builders' merchant will have single size stone in big bags, with more or less variety according to local fashions. It can be expensive though when it is made from attractive stone for paths etc. I bought some last week called Cotswold stone (It is white and will be exposed) for £78 / bag whereas the sharp sand or gravel on the same delivery was £42. If there is a local stone then this should be cheaper. As it happens, it is for laying inside gravel grid specifically to be free draining. The original went in about 15 years ago and has had a lot of use. We are cleaning the messy top off and releveling some areas. Because of erosion it is not open textured any longer and it puddles locally where it has dropped. But because it is on a slope, any that doesn't make it downwards will run off because of the slope. Then it is caught in a perimeter layer of gravel and french drain.. To summarise. Single size stone or gravel is SUDS in itself as long a it is deep enough, to hold the rainfall, and contained . A slope is up to you, but where would you then catch any runoff? Expand Thanks for the info. I had planned everything without the fall on the lower level but it could be done. There is already an existing French drain which I’ve highlighted in a blueish colour, so I could put a fall towards that. Or… I could just make it level and see what happens 😬 Link to comment Share on other sites More sharing options...
saveasteading Posted April 18 Share Posted April 18 On 18/04/2024 at 14:35, machtucker said: make it level and see what happens Expand do it very thoroughly then, as the slightest dipping will allow puddling. Or if your single size stone is deep it might hold all the rain. Just remember that only about 1/3 of the volume is voids if it is single size, or 1/4 if there is some variation.. Link to comment Share on other sites More sharing options...
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