DraughtBusters

Energy saving advice and help

  • Facebook
  • Twitter
  • About
    • Our Aims
    • Flyers, articles and reports
    • What people say about us
    • Frequently asked questions
    • Press releases
    • Contact us
  • Draught proofing
    • How to get started
    • Front Door
    • uPVC door problems
    • Why draughts?
    • Tools and Materials
    • Redundant AirBricks
    • Windows and doors
    • Floors
    • Loft and first floor ceilings
    • Loft Traps
    • Draughts and condensation
    • Draughts and types of damp
  • Lockdown suggestions
    • UPVC window seals
  • Finding Draughts
    • Basic Advice
    • Dry lined homes
    • Modern timber frame
    • Victorian terraced houses
    • Chalet Bungalow
    • Cross walled homes
    • Early cavity wall homes
    • Concrete panel houses
    • Solid stone and cob homes
  • Going further
    • Cost-benefit analysis of improvements
    • Controlling your heating system
    • Upgrading to Underfloor Heating
    • In House Winter Cooling Systems
    • Problems with dot and dabbed walls
    • Heat loss from unused chimneys
    • Draughts in the first floor void
    • Around openings in walls
    • A beautiful window
    • Habits to save energy in the kitchen
  • Galleries
  • What’s New?
    • UPVC window seals
    • What is going on under your bath?
    • Surveys
    • A Partially Deconstructed Wall
    • DraughtBusters Winter Report Dec 2019
    • Summer Condensation
    • Why so many flat roofs fail
    • Lead Pumping
    • Spots on a ceiling
    • Rising damp
    • DPC cold bridging dangers

DPC cold bridging dangers

There is a widespread misapprehension that damp proof courses (dpc’s) stop all damp, there is no way for them to stop condensation from forming on top of them. Unfortunately dpc’s are by their nature nearly always located at a crucial cold bridge, so too often in timber frame and SIPs constructions there is a risk of condensation forming in very cold weather or with high humidity indoors on top of the dpc, this is in direct contact with the wooden sole plate, repeated dampness from this source will eventually cause rot even where treated timber has been utilised.  

I had protracted discussions with a structural insulated panel manufacturer a couple of years ago when I was the sustainability consultant and project adviser on the design team for a low energy new building. I insisted on additional insulation in the cavity to protect the dpc, top block sole plate and bottom rail from getting too cold (it was the coldest thermal bridge in the house). Initially the  SIPs technical department stated categorically that no insulation would be allowed anywhere outside of the SIPs on any account and that if we wanted more insulation it would only be allowable if affixed to the inside of their panels.  After some discussion and my asking a lot of awkward questions they relented and allowed us to build in a 600mm high sheet of 50mm eps fixed over the wall plate area, covering a band 300mm above and below dpc, the breather membrane was carried over and down the outside of this insulation which had a chamfered top edge so that any water in the cavity would be directed down the cavity to drip away well below dpc. This was a major breakthrough and calls into question the longevity of early SIPs buildings where there could be problems with the sole plates getting  damp from condensation on top of the dpc due to thermal bridging. All this also equally applies to timber frame construction too, probably not a significant risk for early poorly insulated frames but as insulation levels increase the risk increases.

Tony Cowling – December 2018 

Covid recovery package to include vouchers to help pay for energy saving retrofits

July 7, 2020

Vouchers of up to £5000 to help pay for energy saving home improvements are one of the measures expected to be announced by the chancellor, Rishi Sunak, in tomorrow's (Wednesday 8 July 2020) statement … [Read More...]

Lockdown Actions

June 2, 2019

UPVC Door Problems

December 23, 2017

PM lends support

February 8, 2017

Energy Saving information available from Repair Café events this winter

December 15, 2016

[Media Release] Repair Café with Energy Saving Seminar

December 13, 2016

  • Downloads
  • FAQs
  • Links
  • Contact us

A project of

Transition Town Reading

Partnered with

Reading Borough Council

Supported by

Reading Rotary Club

Copyright © 2021 · Outreach Pro on Genesis Framework · WordPress · Log in