Hi all,
First of all i want to say what a wonderfull and informative site you have here. I have been able to answer a lot of my questions just by browsing here.
Just a couple of questions i need help with.
1. I need 5 tonnes of DTp Type 1, I already have 1 tonne of white stones (they range in size from a 5p piece to just over 50p peice size) which used to border the old lawn, can i utilise these in the sub-base and add 4 tonne of DTp Type 1 to them?
2. I am just using the drive (25 sq metres, slightly over 8 metres in length) to park 1 car on, do i need 50mm or 60 mm blocks?
3. Does th 50mm of grit sand need to be compacted (I think it does)?
4. If so, when i lay the blocks, do i lay them directly onto the compacted grit sand or do i add a thin layer of loose grit sand on top of the 50mm compacted grit sand to bed the blocks on?
Help with my first ever block paving project
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84-1093879891
1 - scatter the old stone over the surface of the excavated sub-grade and then top up with genuine DTp1. Keep the old rubbish to a thin, base layer blinding over the whole area, rather than a 'block' of material in just one spot.
2 - 50mm will be fine, 60mm would be better, but it really doesn't matter for a residential driveway.
3 - 50mm is the maximum recommended thickness after compaction. Read the Screeding page for a fuller explanation.
4 - see above. I recommend the pre-compaction method, as it gives the best results in the longer term.
Good luck and let us know how you get on! :)
2 - 50mm will be fine, 60mm would be better, but it really doesn't matter for a residential driveway.
3 - 50mm is the maximum recommended thickness after compaction. Read the Screeding page for a fuller explanation.
4 - see above. I recommend the pre-compaction method, as it gives the best results in the longer term.
Good luck and let us know how you get on! :)
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Sirrocco
- Posts: 3
- Joined: Sat Jun 14, 2003 5:56 pm
Hi again,
I have finally dug out everything to 200mm and will soon be comencing laying the hardcore (dtp1) and compacting it.
Once i have done this i plan to lay the edging soldiers. I have been told it is a lot easier to lay the edging blocks on a dry mix and then lightly run a hose over them. Would you recommend this or is it best to mix the morter up?
Also i am concerned about weeds and other plant life growing underneath the blocked area. Again i have been told the black sheeting stuff that can be bought from B&Q specifically for stopping this is not very good and i should use heavy duty plastic sheeting. What would you advise for this? And at what stage should i lay this sheeting? Prior to laying dtp1 or prior to laying grit sand or prior to laying the blocks?
Also my driveway has a gentle slope to it running away from the house. Is it better to start laying the blocks from the bottom and working up(so that there are no cut blocks at the begining of the drive where the initial impact of the car will be felt) or is it best starting at the top and working downwards?
I have finally dug out everything to 200mm and will soon be comencing laying the hardcore (dtp1) and compacting it.
Once i have done this i plan to lay the edging soldiers. I have been told it is a lot easier to lay the edging blocks on a dry mix and then lightly run a hose over them. Would you recommend this or is it best to mix the morter up?
Also i am concerned about weeds and other plant life growing underneath the blocked area. Again i have been told the black sheeting stuff that can be bought from B&Q specifically for stopping this is not very good and i should use heavy duty plastic sheeting. What would you advise for this? And at what stage should i lay this sheeting? Prior to laying dtp1 or prior to laying grit sand or prior to laying the blocks?
Also my driveway has a gentle slope to it running away from the house. Is it better to start laying the blocks from the bottom and working up(so that there are no cut blocks at the begining of the drive where the initial impact of the car will be felt) or is it best starting at the top and working downwards?
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84-1093879891
Sirrocco writted...
I have been told it is a lot easier to lay the edging blocks on a dry mix and then lightly run a hose over them. Would you recommend this or is it best to mix the morter up?
It's best to lay the edge courses on a semi-dry mix of concrete, as described on the main site. There's adequate moisture in the sands and gravels to initiate curing of the cement, so no need to add extra water by hose, by bucket or by any other means. You can use a wetter mix for the haunching, but a semi-dry mix is ideal for bedding.
Wedds - other than the really pernicios, nuclear-bomb proof weeds such as Japanese Knot Weed and Equisetum, the vast majority of weeds will not grow through a properly constructed block pavement. There's 200mm of heavily compacted weed-unfriendly material between the sub-grade and the surface, and your average dandelion or daisy does not stand a chance of getting through that lot, whether there's a weed membrane there or not.
However, weeds will settle onto the surface of the completed pavement and grow into the joints, and no weed membrane can stop that, regardless of where it's positioned.
So, a weed membrane is not necessary beneath a properly constructed block pavement, and to use a sheet of polythene rather than a proper permeable membrane is a certain recipe for disaster. I don't know who's giving you all this duff information, but maybe you should start drinking in a different pub, because the expert you have there is a right numpty!
The use of membranes beneath block pavements is covered elsewhere on the website, but their purpose is to add stability to the construction, not to prevent weeds. Weed membranes are fine benath mulches and other loose surface dressings, but they are a complete and utter waste of time and money beneath a properly paved surface.
With any form of paving, you always start to lay at the bottom of a slope and work your way uphill. If you do it t'other road round, the paving starts to slips away from you as you lay it! :)
I have been told it is a lot easier to lay the edging blocks on a dry mix and then lightly run a hose over them. Would you recommend this or is it best to mix the morter up?
It's best to lay the edge courses on a semi-dry mix of concrete, as described on the main site. There's adequate moisture in the sands and gravels to initiate curing of the cement, so no need to add extra water by hose, by bucket or by any other means. You can use a wetter mix for the haunching, but a semi-dry mix is ideal for bedding.
Wedds - other than the really pernicios, nuclear-bomb proof weeds such as Japanese Knot Weed and Equisetum, the vast majority of weeds will not grow through a properly constructed block pavement. There's 200mm of heavily compacted weed-unfriendly material between the sub-grade and the surface, and your average dandelion or daisy does not stand a chance of getting through that lot, whether there's a weed membrane there or not.
However, weeds will settle onto the surface of the completed pavement and grow into the joints, and no weed membrane can stop that, regardless of where it's positioned.
So, a weed membrane is not necessary beneath a properly constructed block pavement, and to use a sheet of polythene rather than a proper permeable membrane is a certain recipe for disaster. I don't know who's giving you all this duff information, but maybe you should start drinking in a different pub, because the expert you have there is a right numpty!
The use of membranes beneath block pavements is covered elsewhere on the website, but their purpose is to add stability to the construction, not to prevent weeds. Weed membranes are fine benath mulches and other loose surface dressings, but they are a complete and utter waste of time and money beneath a properly paved surface.
With any form of paving, you always start to lay at the bottom of a slope and work your way uphill. If you do it t'other road round, the paving starts to slips away from you as you lay it! :)
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Sirrocco
- Posts: 3
- Joined: Sat Jun 14, 2003 5:56 pm
Thanks Tony,
I don't consider my drinking buds to be the experts, thats why im double checking with you :)
One more quick question for now.
My driveway will be encased with 2 lines of soldiers (one up each side), i know that i have to lay the outside line to give the blocks stability when laying but do i have to lay the inside set before aswell?
The reason i am asking this is - on your block patterns page http://www.pavingexpert.com/blocks.htm#desn if those blocks are 200mm * 100mm then the area they cover is 1.4 square metres, is this usually exact? I want to minimise block cutting down the inside edge of the drive and my drive will be 3.0 metres wide exactly. Therefor if i lay both beds of soldiers i will have a gap of 2.6 metres to fill with block. With the gap being an exact multiple of 200mm and 100mm is it unlikely i will have to cut any blocks down the inside edge? Or as i lay the blocks will a few mm extra get used up as i work my way across?
Sorry if these questions seem pretty basic to you but i dont want to balls the job up :)
p.s. I will be using the 90 herringbone pattern
(Edited by Sirrocco at 1:37 pm on June 19, 2003)
(Edited by Sirrocco at 1:39 pm on June 19, 2003)
I don't consider my drinking buds to be the experts, thats why im double checking with you :)
One more quick question for now.
My driveway will be encased with 2 lines of soldiers (one up each side), i know that i have to lay the outside line to give the blocks stability when laying but do i have to lay the inside set before aswell?
The reason i am asking this is - on your block patterns page http://www.pavingexpert.com/blocks.htm#desn if those blocks are 200mm * 100mm then the area they cover is 1.4 square metres, is this usually exact? I want to minimise block cutting down the inside edge of the drive and my drive will be 3.0 metres wide exactly. Therefor if i lay both beds of soldiers i will have a gap of 2.6 metres to fill with block. With the gap being an exact multiple of 200mm and 100mm is it unlikely i will have to cut any blocks down the inside edge? Or as i lay the blocks will a few mm extra get used up as i work my way across?
Sorry if these questions seem pretty basic to you but i dont want to balls the job up :)
p.s. I will be using the 90 herringbone pattern
(Edited by Sirrocco at 1:37 pm on June 19, 2003)
(Edited by Sirrocco at 1:39 pm on June 19, 2003)
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84-1093879891
It's never a good idea to attempt to predict the exact width of a block paved area prior to laying. In theory, you want a 3m wide driveway, and you have two edge courses, laid as soldiers, each 200mm wide, so, you'd think that 26 blocks, each 100mm wide, laid between the edge course would do the job perfectly, but it ain't that simple.
There's a 3mm joint between the blocks, so you need to allow for that. However, assuming that each joint will be exactly 3mm is fatal, as the figure of 3mm is an ideal, and, in real life, the joint will more than likely be somewhere in the range 2-5mm. So, if you laid 26 courses of block paving, you could end up with a width of between (26 X 102mm) 2.65m and (26 X 105mm) 2.73m, a range of 80mm.
If you want to be sure of using as few cut blocks as possible, then the only way to work is as follows....
1 - lay one edge course on concrete bed and then haunch the blocks so they are firmly held in place (unless they are up against a firm fixture, such as a wall). This is your fixed edge course.
2 - lay the opposite edge course on semi-dry concrete bedding, with ample spread of the bedding to the outside edge of the blocks. Lay these blocks at the minimum theoretical separation from the fixed edge course (2.65m, as calculated above). This is your free edge course.
3 - prepare your screed and lay the blocks as per normal instructions. This is the body of the paving.
4 - adjust the position of the free edge course blocks so that they give a tight joint against the full blocks of the body paving. The edge course blocks can move out on the generously wide bed you prepared for them in step 2 above. Just slide them over carefully, so that the level is not affected, just the alignment.
Once all of the edge course blocks have been moved as required you should check the alignment with a taut string line, as there will be some deviation, and, if you rely solely on creating a tight joint between the blocks of the body and those of the free edge course, it will look like a crippled dog's back leg. You will have to do a bit of 'give and take' with some joints being a touch wider than other so that the edge course looks straight.
5 - Once you're happy with the alignment of the free edge course, fix it in place with concrete haunching.
6 - cut in the half-blocks to complete the body paving, and then sand-up the joints. Leave the consolidation (wackering) until the following day when the freshly-placed haunching concrete will have set and will be better able to withstand the force of the vib plate.
7 - Pub! :)
These Q's aren't basic - they're fundamental to the construction of a decent driveway, and the whole purpose of this forum is to answer these fundamental questions. :)
There's a 3mm joint between the blocks, so you need to allow for that. However, assuming that each joint will be exactly 3mm is fatal, as the figure of 3mm is an ideal, and, in real life, the joint will more than likely be somewhere in the range 2-5mm. So, if you laid 26 courses of block paving, you could end up with a width of between (26 X 102mm) 2.65m and (26 X 105mm) 2.73m, a range of 80mm.
If you want to be sure of using as few cut blocks as possible, then the only way to work is as follows....
1 - lay one edge course on concrete bed and then haunch the blocks so they are firmly held in place (unless they are up against a firm fixture, such as a wall). This is your fixed edge course.
2 - lay the opposite edge course on semi-dry concrete bedding, with ample spread of the bedding to the outside edge of the blocks. Lay these blocks at the minimum theoretical separation from the fixed edge course (2.65m, as calculated above). This is your free edge course.
3 - prepare your screed and lay the blocks as per normal instructions. This is the body of the paving.
4 - adjust the position of the free edge course blocks so that they give a tight joint against the full blocks of the body paving. The edge course blocks can move out on the generously wide bed you prepared for them in step 2 above. Just slide them over carefully, so that the level is not affected, just the alignment.
Once all of the edge course blocks have been moved as required you should check the alignment with a taut string line, as there will be some deviation, and, if you rely solely on creating a tight joint between the blocks of the body and those of the free edge course, it will look like a crippled dog's back leg. You will have to do a bit of 'give and take' with some joints being a touch wider than other so that the edge course looks straight.
5 - Once you're happy with the alignment of the free edge course, fix it in place with concrete haunching.
6 - cut in the half-blocks to complete the body paving, and then sand-up the joints. Leave the consolidation (wackering) until the following day when the freshly-placed haunching concrete will have set and will be better able to withstand the force of the vib plate.
7 - Pub! :)
These Q's aren't basic - they're fundamental to the construction of a decent driveway, and the whole purpose of this forum is to answer these fundamental questions. :)