Cavity Wall - No Insulation

[kylelnsn]

Hi all,

 

Long time lurker here, dipping my toe in the water.

 

We are currently looking to take on a property that is partially constructed. At present the cavity wall is is uninsulated. I am a little hesitant to fill it with beads etc retrofit wise, and currently planning EWI (External Wall Insulation) as the primary insulation method...  I have a few queries on this;

 

• Are we going to create any future issues by doing this?
• Is there anything we need to manage by doing this?
• What thickness of insulation would we have to add to the exterior to meet building regs?
• What thickness is the norm?
• Are we missing a better alternative?

 

I am totally open to all options, and interested to see others thoughts on this.

 

[PeterW]

Welcome

 

how wide is the cavity and why the reluctance with beads..??

 

Using EWI with a standard cavity wall will end up over 450mm just to get to BRegs so it’s a huge amount of wall with a pointless cavity. 

 

 

[Ed Davies]

Would you ventilate that cavity? If so, to where? If the outside then it'll bypass the insulation nicely. I suppose you could ventilate to inside but that'd be a rather unusual thing to do.

[kylelnsn]

6 minutes ago, PeterW said:

Welcome

 

how wide is the cavity and why the reluctance with beads..??

 

Using EWI with a standard cavity wall will end up over 450mm just to get to BRegs so it’s a huge amount of wall with a pointless cavity. 

 

 

 

I always have an image of drilling a hole somewhere, or fitting more windows etc in the future and the cavity slowly emptying before my eyes! ?As well as the horror stories I read online about them creating damp etc. 

 

Its a standard cavity, so around 100mm inside skin, 100mm cavity and 100mm outside skin. We loosely looked at 75-100mm to fit the outside.

 

2 minutes ago, Ed Davies said:

Would you ventilate that cavity? If so, to where? If the outside then it'll bypass the insulation nicely. I suppose you could ventilate to inside but that'd be a rather unusual thing to do.

 

I presume we would ventilate to the outside... using weep vents I guess?!

[PeterW]

Beads are glued together - they spray them with PVA as they go into the cavity so set semi solid. 

 

Damp bridging is something that used to occur but is extremely rare now. 

 

Is it brick exterior leaf..?

[the_r_sole]

.

Edited September 26, 2019 by the_r_sole

[Brickie]

9 minutes ago, the_r_sole said:

what do you mean by "partially constructed" - is someone building a house that has no insulation?!

Possibly-blown in beads is not uncommon on New Builds. 

[Declan52]

Countryside here has lots of partially started builds where the people have ran out of money and the bank have taken it over.  

As Peter says the beads are blown in at high pressure and are coated with so end up solid. Will be the easiest method of doing what you need to do. 

I would be checking everything like  dpc, how plumb are the walls, how square are door and window openings. 

Did the previous owners have building control do inspections up to what point it is at now and can you get your hands on these??

[kylelnsn]

On 01/11/2018 at 21:07, the_r_sole said:

what do you mean by "partially constructed" - is someone building a house that has no insulation?!

 

Its an abandoned project, started in the 90's but never got finished, at the time they didn't fill the cavities. So the ground floor has no insulation. Only partially filled as standard on the front face.

 

The building looks good otherwise, as you say DPC is inplace, openings are good, and the roof that was added last year is really nicely put together, and over specced timberwise.

 

I will see who locally does injection and go from there I guess! Im still worried about damp though