External wall insulation - Timber frame

Heedtheadvice

Just a misunderstanding there about CWI but I agree... do not do it! The cavity is there for a reason, to provide airflow between the outer skin and the  Timber to prevent decay. Hence not liked - the Timber frame is structural!!

EWI on the other hand  gives, an extra layer of waterproofing as well as insulation.

Provided it is quite covering, does not detract from the visual appearance and is properly applied   (!) then it can be beneficial....but watch out for the cost.

anon_ymous

Heedtheadvice said:

Just a misunderstanding there about CWI but I agree... do not do it! The cavity is there for a reason, to provide airflow between the outer skin and the  Timber to prevent decay. Hence not liked - the Timber frame is structural!!

EWI on the other hand  gives, an extra layer of waterproofing as well as insulation.

Provided it is quite covering, does not detract from the visual appearance and is properly applied   (!) then it can be beneficial....but watch out for the cost.

Thanks 

In one way, I kinda wanna go for EWI before IWI,  given I can see it as hurting now but not in the future

I'll also be initially getting solar panels anyway tbf 

chris_n

waqasahmed said:

Heedtheadvice said:

Just a misunderstanding there about CWI but I agree... do not do it! The cavity is there for a reason, to provide airflow between the outer skin and the  Timber to prevent decay. Hence not liked - the Timber frame is structural!!

EWI on the other hand  gives, an extra layer of waterproofing as well as insulation.

Provided it is quite covering, does not detract from the visual appearance and is properly applied   (!) then it can be beneficial....but watch out for the cost.

Thanks 

In one way, I kinda wanna go for EWI before IWI,  given I can see it as hurting now but not in the future

I'll also be initially getting solar panels anyway tbf 

If there needs to be airflow in the cavity there is no point in EWI. You are allowing cold air past the insulation so totally negating the effect! 

Reed_Richards

My bungalow is timber frame. There is no direct access that I have ever found from the air in the cavity to either the inside or the outside.  But in the loft there is only the boards at the gable ends between the cavity and the air in the loft.     

Heedtheadvice

chris_n said:

waqasahmed said:

Heedtheadvice said:

Just a misunderstanding there about CWI but I agree... do not do it! The cavity is there for a reason, to provide airflow between the outer skin and the  Timber to prevent decay. Hence not liked - the Timber frame is structural!!

EWI on the other hand  gives, an extra layer of waterproofing as well as insulation.

Provided it is quite covering, does not detract from the visual appearance and is properly applied   (!) then it can be beneficial....but watch out for the cost.

Thanks 

In one way, I kinda wanna go for EWI before IWI,  given I can see it as hurting now but not in the future

I'll also be initially getting solar panels anyway tbf 

If there needs to be airflow in the cavity there is no point in EWI. You are allowing cold air past the insulation so totally negating the effect! 

Good point Chris!

anon_ymous

chris_n said:

waqasahmed said:

Heedtheadvice said:

Just a misunderstanding there about CWI but I agree... do not do it! The cavity is there for a reason, to provide airflow between the outer skin and the  Timber to prevent decay. Hence not liked - the Timber frame is structural!!

EWI on the other hand  gives, an extra layer of waterproofing as well as insulation.

Provided it is quite covering, does not detract from the visual appearance and is properly applied   (!) then it can be beneficial....but watch out for the cost.

Thanks 

In one way, I kinda wanna go for EWI before IWI,  given I can see it as hurting now but not in the future

I'll also be initially getting solar panels anyway tbf 

If there needs to be airflow in the cavity there is no point in EWI. You are allowing cold air past the insulation so totally negating the effect! 

Ah, so it'd basically cause damp? Would IWI still be useful? 

anon_ymous

Reed_Richards said:

Timber frame properties only have a small cavity (50 mm) and a lot of insulation between the cavity and the inside of the house (100 mm).  Even if you did insulate the cavity it would be the difference between 100 mm of insulation and 150 mm of insulation, not very great.

Timber frame walls are relatively well insulated compared to other types of construction but if you wanted more insulation it would probably be cheaper to add it on the inside rather than on the outside.  

A tad related, but is it possible for my house to be a timber frame and the next door house to be cavity wall? They're both semi detached houses, so it seems odd that's the case according to the EPC 

Unless the cavity wall side of things, is their little extension in the back yard? Doing a look on my street, it seems more than half have CW and less than half have timber, despite all of them being semi detached.  I'm not sure how that works?

I'm mostly asking as I've currently got damp, and it's on a wall that's directly connected to the neighbour, where they've got an extension.  

Reed_Richards

Here is the interior of my loft, looking at the gable end.  You will see that the construction of the wall is not brick or block but sheet wood.  That's the giveaway that the house is timber-framed and also that sheet of wood is all that is separating the air in the loft from the air in the cavity.

It seems very unlikely that a street of houses all built at the same time by the same builder would mix timber frame and CW.  But I don't think builders building an extension are likely to use timber frame for the extension.  

anon_ymous

Reed_Richards said:

Here is the interior of my loft, looking at the gable end.  You will see that the construction of the wall is not brick or block but sheet wood.  That's the giveaway that the house is timber-framed and also that sheet of wood is all that is separating the air in the loft from the air in the cavity.

It seems very unlikely that a street of houses all built at the same time by the same builder would mix timber frame and CW.  But I don't think builders building an extension are likely to use timber frame for the extension.  

That makes a lot of sense then 

So, I've got a roof in roof, and their extension goes into their back yard.  I guess we'll see who's house is causing that issue. 

chris_n

waqasahmed said:

chris_n said:

waqasahmed said:

Heedtheadvice said:

Just a misunderstanding there about CWI but I agree... do not do it! The cavity is there for a reason, to provide airflow between the outer skin and the  Timber to prevent decay. Hence not liked - the Timber frame is structural!!

EWI on the other hand  gives, an extra layer of waterproofing as well as insulation.

Provided it is quite covering, does not detract from the visual appearance and is properly applied   (!) then it can be beneficial....but watch out for the cost.

Thanks 

In one way, I kinda wanna go for EWI before IWI,  given I can see it as hurting now but not in the future

I'll also be initially getting solar panels anyway tbf 

If there needs to be airflow in the cavity there is no point in EWI. You are allowing cold air past the insulation so totally negating the effect! 

Ah, so it'd basically cause damp? Would IWI still be useful? 

It's not that it would cause damp, just that cold air would be on the supposed warm side of the insulation so negating its usefulness. IWI would help but you would need to find out where in the construction any condensation is likely to occur.