Hi All, Im in the process of renovating an old farmhouse and need to put a timber floor on joists/battens on top of an old concrete floor. This is to allow me to insulate and run services. Due to height limitations there will be no gap between concrete and underside of joist (apart from some localized packing to achieve level) and i am unsure if the slab gets damp as it was an old stable. Do I need do lay a DPM directly onto the concrete and does my construction plan sound ok? Thanks.
If it was an old stable, they've probably just thrown the slab in without a DPM. Your plan is fine and I'd certainly lay visqueen. You'll be piercing the visqueen when you send your fixings through. Due to that reason, I'd use galvanized screws and flood the screw holes with silicone to help prevent moisture issues. Alternatively, you could use a liquid DPM system and glue the battens down. That would be the best option in my opinion, however, that will by far be the most expensive option.
