decking/timber stumps/potential rot

hi all.

just a question on the best way to set in timber stumps.

currently having a decking installed, and the timber stumps have been installed with concrete filled to about 5cm below ground level. this worries me as with the overnight rain, there are pools of water around most stumps. spoken with the builder who assures me that this is the correct technique, and he will backfill it with soil/clay.

wouldn't it have been much better to fill concrete to above ground level, so that water runs away from stumps?

should i be concerned?

thanks for any help, and apologies for incorrect terminology etc. not really well versed in the arts of woodwork.

john.

The best way to install timber posts is on stirrups concreted into the ground. If the posts are concreted in ground it is best to mound the concrete above ground level as you said, not put it below g/l. Ideally the post will sit on a base of gravel to aid drainage- concrete under the post is also a sure way to rot the post. Also check that he has used either h4 treated pine or an inground class1 hardwood such as ironbark.

Cheers
Michael