Early 1959/60 Mini's had plain flat outer sills as part of the floor with no drain holes......the inner sills were seperate panels lapped inside under the carpet, however any water getting in the sills ended up under the carpets.....so the BMC factory then foam filled the sills. Some of the least rusty Mini's with long lasting sills were the early foam filled cars. However when they did eventually need welding the foam was a nightmare to get rid of before welding could commence!
