Solid wall Internal Wall Insulation (Warm Batten) design

[scottishjohn]

11 hours ago, Redbeard said:

Free-standing stud wall with insulation and adequate x-vent behind is great, and ventilation may be adequate for a whole elevation with say 4 air-bricks per storey. If you have studs against the wall then you need an 'in' and an 'out' (say 225 x 150 each) between *each pair of studs'. That's a hell of a lot of air-bricks, ranging from 'not aesthetically pleasing' on, say, brick walls to virtually impossible of rubble-filled stone with a loose core. https://assets.publishing.service.gov.uk/media/614b30aad3bf7f718a54c0be/iwi-guidance.pdf 

 

you do not need air bricks ,and air bricks should be ducted through both walls to under side of house to vent under the suspended floors ,not just in outer layer to make a draft up the cavity 

 

just let it happen naturally --warm air rises and so takes moisture with it  and we are talking about an old house which we want to dry out  or keep it dry at back of wall

as for fire risk you fit intumescent fire stops  which only expand if there is a fire and blocks off the cavity 

 as for getting condensation on VCL--thats shows your insulation is not good enough  and or lots of air leaks through it  -if correct the insulation should stop any chance of condensation 

 assuming you are  not hydroponically growing weed  inside 

 

 

[scottishjohn]

4 hours ago, Annker said:

One issue I dont have is moisture passing through the walls from outside. 

The brickwork is the house bone dry, you cannot imagine how dry.

If I handle the bricks (I've knocked through many openings) for a day the skin on my hands opens up, the bricks literally pull the oil from them and we're not talking office boy hands here either 😂

that will be internal walls which are dried from both sides from heat in house  for 100years 

the outer walls are different as one side can be wet +cold and other heated by internals  of house and thats where you will get  condensation  if the dew point is reached 

kile the inside of a  single glazed window on a cold morning.

 

 I doubt you will have any DPC in a victorian house so thats the other place  capillary action from water in the ground  sucks it up  which is why we have a DPC to stop it happening  and why with no DPC it pays to have ground level outside house  a lot lower than floor l

there was reason why expnsive big old houses had steps up to entrance level,  even if they did not have cellars  

 to keep floor joists etc well above any rising damp from the foundations 

 as genaral rule rising damp will only go up  to a metre maximum

 

on modern house with concrete floors etc the floor level will always be at least 150mm  minimum above the ground level  outside 

 

 if not then lots of french drains and pea gravel to soak away any water from the walls

 

 look at the detail for dpc under a slab and where it finishs inside the walls above the floor level into the walls usually where the  outer wall DPC is  and your TF kit starts on dwarf walls