Log cabin on concrete base letting in water and damp Questions answered and a range of solutions on problems and issues encountered with timber framed buildings

[Shayshay]

We had a concrete base installed but the guys didn’t put a dpm under the concrete and assured us it was not needed, mainly because they had started to pour the concrete I guess and forgot the put in the dpm! The concrete base was also dipping slightly in centre and rain was sitting in the middle prior to cabin being up.
Anyway the log cabin has been up about a month and water puddles were forming in the cabin. For this reason we didn’t finish laying the floor until the water was resolved. Now after adding guttering, trimming some dpc that was not level to the timber frame on outside we have less puddles, but still a lot of damp areas. The log cabin frame is on dpc strips, well some of the frame is. What can we do to resolve this damp floor before laying insulation and wood flooring?

[stoneyboy]

Hi shayshay,
Presumably the cabin has been built direct on the concrete base. You could add an internal DPM on the surface of the concrete and lap up the walls but the bottom of the frame will be damp and subject to rotting.
Regards S

[Shayshay]

Yes the frame is on the concrete base and some of it has strips of dpc between concrete and timber frame.

The cabin fitter suggested cutting the inside frame and laying dpm and then screwing the timber frame back in. But I’m not sure if that a good idea now?
Really need a long term solution to avoid rotting frame and timbers. And also avoid any potential damage to the building construction.

[stoneyboy]

Hi shayshay,
With the cabin direct onto the concrete slab it will be difficult to find an easy solution - rain will always drive in and under the edges.
If you can jack the cabin up, lay 100mm concrete blocks to match the external wall footprint. Lay a DPM over the floor and take this up and onto the concrete blocks, fit a DPC on the blocks and lower the cabin down. There should be some sort of breathable membrane under the outer cladding and the membrane should be taken partly down the concrete blocks and covered with the external cladding.
There may be other solutions but I doubt they will be successful if the cabin remains direct on the concrete slab.
Regards S