Compress Straw Boards Walls

[LukLagun]

So we in process of refurnishing out 1960's bungalow.
It's MK2 Trust Steel Construction with London Brick outside and 50mm Straw Boards Panels fixed on the metal frame on inside.

So far i did one room and did remove 50mm starw boards on window side wall then i did :

build wooden frame out of tanalised wood
Apply roofing breathable membrane
100mm Cavity Insulation
18mm Plywood
15mm Blue Sound Proofing Plasterboards
75mm insulation in partition walls

Floor was also done similar way :

roof batten under floor joists
roofing breathable membrane
100mm insulation
DPM Membrane on top
18mm T&G Floorboards

All above made room lot warmer compering to rest of the house.
On top of that we going to fit new 3tri glazed windows in whole house.
We also will be adding Full MVHR system to eliminate any dampness issue in further.

Will be starting work on our main bedroom and been think to leave existing 50mm straw boards in place. This would save me lotz of time.
I had a look on R-Value and look like compress straw board are around 1.5 R-value so that means they have really good insulation prosperities.

Whole floor will be done same way as was done in smaller bedroom.
My plan for walls is to :

leave exiting straw boards in place ( as long there is no moisture damage)
fix 18mm plywood ( so we can fix something to walls if we want)
fix 25mm insulated plasterboards on 2 outside walls
rest to be done in 15mm plasterboards with 75mm insulation in stud walls,


Is this good way to do it or should i remove the straw boards and do same what i did in small bedroom.

Been trying to find more info online if anyone did similar thing but no look so far ???

Much appreciated for advice.

Luki

 

[endecotp]

> I had a look on R-Value and look like compress straw board are around 1.5 R-value

Where did you find that number?

I would expect compressed straw to be about half as good as modern rockwool, fibreglass or similar, for the same thickness.

It will be a relatively good sound barrier, though. You don't want to end up with a warmer but noisier house, so consider using acoustic insulation batts if you remove the straw. These have similar thermal properties to regular rockwool, but are heavier and so absorb more sound.

Insulated plasterboard seems to cost more than buying the insulation and the plasterboard separately. Which is easier to fit is a matter of debate.

I'm unsure about the membrane. Maybe someone else will comment on that. What are you hoping to achieve with it?