DPC bridged internally by concrete slab

[John Williamson]

We have a detached garage which we are looking to convert to living accommodation. Whilst trenching for utilities we noticed that the damp proof course has been bridged by the concrete slab. This is inside the garage, the external levels are below. Construction is single skin lightweight blocks with a rendered exterior.


Just wondering, should I be concerned about this? What could I do to remediate? Do I need to dig out the slab, excavate and re-lay or is there a simpler/cheaper option?







Original plan was to follow this up to the screed layer. Is this still applicable or do I need to deal with the bridged DPC first?

 

[Deleted member 292770]

yikes

 

[John Williamson]

yikes

Surely not bad enough for a yikes? Worst case scenario dig out concrete, lay a new slab

 

[Deleted member 292770]

Sounds like a plan if your up for it . don’t forget a dpm this time.And some insulation if your feeling flush.

 

[John Williamson]

Sounds like a plan if your up for it . don’t forget a dpm this time.And some insulation if your feeling flush.

Sorry I don't think answers the question. I have seen plenty of info on the outside ground levels being 150mm below the DPC. The question here is does the same apply to the inside slab?

Probably I did not write the question well. It should have read "is it necessary for the floor slab to finish below the DPC if there will be a DPM before floor insulation is laid, considering the DPM will be rising up the walls?" i.e. is the internal bridging of the DPC with the slab relevant if the plan is to lay the flooring as per picture above?

 

[Deleted member 292770]

.

 

[noseall]

There is nothing to be concerned about regards an internal floor finishing higher than the DPC. You could build it up to the window sills if you wanted to.

Lower could be a problem if the DPM has been poorly installed.

 

[John Williamson]

There is nothing to be concerned about regards an internal floor finishing higher than the DPC. You could build it up to the window sills if you wanted to.

Lower could be a problem if the DPM has been poorly installed.

Thanks so much. Couldn’t find the definitive answer in searches. Not super convinced the existing DPM is any good but this will be mitigated with a decent one and the slip membrane shown above