Posted: Thu Jul 09, 2020 10:50 pm
I've had three quotes for my 85 square meter driveway but the specs are totally different. Existing driveway is block paved sitting on 35mm sharp sand on 100mm concrete pad. There has been some movement on the existing driveway - not awful but noticeable.
Quote 1 - retain concrete base and blind over with Type 1 where necessary, lay 30mm sharp sand, screeded and compacted.
Quote 2- retain concrete sub base, screed with lean mix over low points, screed with sharp sand as normal.
Quote 3 - Install geo textile over MOT type 1 150mm compacted. 50mm sharp sand screeded and compacted.
Contractor 1 - this guy's an Interlay contractor so this really surprised me. He wants to retain the sub base because I have a low single skin wall sitting on the same foundation as the driveway and he's worried that it will be shaken and damaged whilst breaking up the concrete. What surprised me is that he recommended adding type 1 to a concrete sub base.
Contractor 2 just likes concrete sub bases and thinks that it would be unnecessary to break it up and is certain that if he screeds over any low points with a lean mix of concrete then the pavers will not move.
Contractor 3 wants to create a new sub base to a usual spec and isn't worried about damaging the wall and said that he's grind out the edge of the concrete base next to the wall so not creating too much vibration.
I know that building a flexible driveway on top of a concrete sub base goes against all usual specs. But I also know that many old driveways still perform well using that very specification - I recall LLL on this forum mentioning that. Gents, what do you think? Are quotes 1 and 2 doomed to failure and will Quote 3's breaking up the existing concrete base really shake the wall sitting on the same foundation to death, even if carefully cut out?
Any opinions very welcome thanks! All three contractors have given conflicting advice.
Quote 1 - retain concrete base and blind over with Type 1 where necessary, lay 30mm sharp sand, screeded and compacted.
Quote 2- retain concrete sub base, screed with lean mix over low points, screed with sharp sand as normal.
Quote 3 - Install geo textile over MOT type 1 150mm compacted. 50mm sharp sand screeded and compacted.
Contractor 1 - this guy's an Interlay contractor so this really surprised me. He wants to retain the sub base because I have a low single skin wall sitting on the same foundation as the driveway and he's worried that it will be shaken and damaged whilst breaking up the concrete. What surprised me is that he recommended adding type 1 to a concrete sub base.
Contractor 2 just likes concrete sub bases and thinks that it would be unnecessary to break it up and is certain that if he screeds over any low points with a lean mix of concrete then the pavers will not move.
Contractor 3 wants to create a new sub base to a usual spec and isn't worried about damaging the wall and said that he's grind out the edge of the concrete base next to the wall so not creating too much vibration.
I know that building a flexible driveway on top of a concrete sub base goes against all usual specs. But I also know that many old driveways still perform well using that very specification - I recall LLL on this forum mentioning that. Gents, what do you think? Are quotes 1 and 2 doomed to failure and will Quote 3's breaking up the existing concrete base really shake the wall sitting on the same foundation to death, even if carefully cut out?
Any opinions very welcome thanks! All three contractors have given conflicting advice.