Barry Chapman

[Barry Chapman]

We are converting a concrete frame barn that already has 8 courses of 9” blockwork around the perimeter. 
How do we apply a dpc to the existing walls and then onto the polythene DPM on the floor? 
Also is it a cheaper option to go timber frame internally or blockwork? 

[Temp]

Welcome to the forum.

 

Inserting a physical DPC..

 

If you hire someone to do the job I believe they should only charge you 5% VAT which you reclaim on VAT431C at the end. Make sure they know the VAT rate should get 5% before you accept their quote. Best get the quote to say Inc VAT at 5%. If they question this refer them to VAT708. Come back for more advice.

[Temp]

2 hours ago, Barry Chapman said:

How do we apply a dpc to the existing walls and then onto the polythene DPM on the floor? 

 

I think only the DPC in the inner leaf needs to tie into the DPM. Sometimes it's sufficient to just lap the DPM up the wall above the DPC on the inner leaf.

 

You may need to insert weep holes in the outer leaf as well.

Edited April 2, 2023 by Temp

[Iceverge]

5 hours ago, Barry Chapman said:

We are converting a concrete frame barn that already has 8 courses of 9” blockwork around the perimeter. 
How do we apply a dpc to the existing walls and then onto the polythene DPM on the floor? 
Also is it a cheaper option to go timber frame internally or blockwork? 

 

Welcome welcome. 

 

A quick cross section sketch would help.