Forum menu
Me and my house again. Sorry!
After 5 years of detection I have realised that rising damp is a thing . The only wall that hasn't got a DPC in (which is the only one that gets signs of damp) now has a DPC - so yay.
But I am laying a new slate hearth after the sandstone one got stains with the damp and, to be sure, am going to put some visqueen down when laying the new hearth - which I will also then slip underneath the floorboards as shown in red, to stop it tracing into there- as it does now.
All good.
But do I lay the visqueen > mortar > hearth - or
mortar > visqueen > hearth
My very small brain tells me the first option, and also that it might not matter - but I cant find the answer on google -anyone know? 🙂
[img] 
[/img]
Thanks.
What’s underneath the hearth?
The mortar needs to be touching the hearth to bond with it and hold it in place.
Dpm, then mortar then hearth
Did ours before Xmas, DPC, then concrete to raise the level then motar to the hearth. Keep the damp as low down as possible.
Slate used to be used as a dpc probably as its impervious but no doubt somebody will disagree, i would just bed it down
Thanks, nice to have confirmed that my initial thoughts were right!
What’s underneath the hearth?
What you can see in the piccy - soil/coal/rubble/cement and some (probably?) asbestos stuff at the front.
And yes, slate does have the added benefit of being a touch resistant to damp - but being as i need to lay a DPM under the floorboards to prevent it tracing up from beneath the floor level I may as well 🙂
Cheers all, much appreciated.
If damp is that much of an issue I'd be concerned about it rotting the edges of the floor boards. Slate shouldn't need anything in that scenario unless it's otters pocket wet.
Is it a Victorian-designed house? There's possibly a narrow brick arch between the last full span joist and the base of the fireplace/chimney, then a layer of mortar on top (no wood to burn). The brick arch is a pain upstairs when you want to plumb a wash basin pedestal on what was the hearth 🙂
The damp will probably be coming from below the fireplace and up through the arch. You can't easily stop it at source so put the membrane as low as poss. If there is rubble below the hearth then try to clear an air gap