Dot and Dab?

[ifindoubtgiveitaclout]

Hello,
Just bought an old stone terraced house. The walls have quite a lot of hollow patches and some mortar has also come away. I was going to hack off all walls and dot and dab strait onto the uneven stone walls, after giving it a coat of pva. But, a friend suggested that the walls should be rendered first, with a scratch coat and then Dot and Dab on top of this, or leave the mortar on and counter batten the wall and screw plaster board to the timber batten
Could anyone please explain why you would need to scratch coat the stone walls before you Dot and Dab(is it for adhesion puposes or to make the wall more even) and could you advise which would be the better job of the two ideas.

Thanks

 

[1john]

Stone walls need to breathe. I like batten and boarding, you can get the walls nice and straight and true. There is also a nice void to hide pipes and cables, if you are going to go to this effort then perhaps it would be worth while re-wiring, at the very least get a periodic inspection report done. Having to have newly plastered walls hacked apart due to dodgy and faulty wiring is very disheartening.

 

[Richard C]

Don’t dot & dab onto solid external walls, it will create cold spots leading to condensation; any moisture in the walls will also destroy ordinary wall board after not too long at all. Use battening as advised but you also need Duplex boards or a vapour barrier to avoid any problems with damp. You might like to consider using Thermaline boards which will give you additional insulation & provide an integral vapour barrier if you select the right one.