Archive for April, 2011

The Renegade Conservatory Guy who is a respected in the industry for his views, has recently taken interest in my cavity tray and vertical dpc articles and has asked the same basic questions to some of his readers, whether to fit them or not and is there a difference between the sales guys and the technical guys in their views on this issue? (Link to his article at bottom of page) I would like to thank him for his interest and his reader’s views, which range from quite sensible approaches to some that I found comical in content and humour.

In light of such diverse opinions I have decided to publish some more technical information which may or may not, help those who are unsure on the decision they need to make on guaranteeing a waterproof conservatory. (My original article links below)

Do you sell, survey and install cavity trays on Conservatories ? If you don’t sooner or later it will cost you.

Do all Conservatory and Orangery surveyors specify vertical dpc’s against the house walls on Conservatory and Orangery Installations

After many years surveying and managing installations across a very broad area of the country, I can categorically tell you if the house is face brick cavity construction, the only way you can guarantee 100% waterproof integrity of the conservatory is to fit cavity trays. If you don’t then the water ingress is always going to be a roll of the dice. “Some people may have rolled lucky sixes years, but you won’t keep winning on the roll of a dice forever”

It appears there are very varied opinions on whether or not cavity trays and vertical dpc’s are required in certain areas of the country or not. Some offer them as part of the sale. Some opinions are purely based on cost of sale. Some have said, they have never had a single leak in thousands of installations fitted without cavity trays, or vertical dpc’s. Then there were those who stated that they have installed in the Scottish Highlands and had no problems. Others will insist that their areas are classed as “sheltered areas”.

To clarify this point I have published a map that shows areas of wind driven rain and it appears to show only a very small proportion  of the UK as being a “sheltered area”



I think it’s fair to say, that the  majority of good companies fit vertical dpc’s between the conservatory frames and the house wall, but there are some out there that don’t.

Over the years I have seen the costs of remedial works as a result of not fitting vertical dpc’s and the subsequent remedial efforts to rectify the associated damp ingress. I’ve been told by several installation companies lately that they do not fit vertical dpc’s where the conservatory frames meet the house wall.

“My advice is, always fit vertical dpc’s where any conservatory frames abut house walls, why take the chance of possible water ingress. The cost isn’t even worth mentioning in the grand scheme, as it is negligible”

You will all at some time seen damp ingress in the bottom corner of the frame at internal cill and ring beam levels, some people will try to attribute this to poor mastic seals. The fact of the matter is, that you should be able to dry fit a conservatory frame against a house wall installing correctly fitted vertical dpc’s without any water ingress taking place.

“They built houses and fitted timber frames without mastic for years using properly installed dpc’s as water barriers and didn’t have damp ingress problems, provided the dpc’s were correctly”

In this article I have tried to outline the importance of fitting vertical dpc’s where the conservatory frames abut the house wall and inserted a few diagrams to show successful dpc installation methods. (more…)