DIY Doctor UK DIY Forums

HI, I AM DRYLINING A FIRST FLOOR BEDROOM(OUTSIDE) WALL AND I HAVE A NUMBER OF QUESTIONS. THE FIRST IS WHAT IS THE IDEAL GAP BETWEEN THE MASONRY AND THE INSIDE OF THE PLASTERBOARD, ESPECIALLY AS I WANT THE SPACE VENTED. THIS LEADS ON TO MY NEXT QUESTION, WHAT IS THE BEST WAY TO VENT IT. MY NATURAL INCLINATION WOULD BE TO USE THE LOFT AS THE UPPER VENT AND THE LOWER VENT WOULD RUN UNDER THE FLOORBOARDS.
WITH REGARDS TO THE LOFT, I HAVE NO PROBLEM WITH THIS AS THERE IS PLENTY OF LEAKAGE INTO THE OUTSIDE TO CREATE A DRAUGHT, IT IS THE FLOORBOARD SPACE I AM WORRIED ABOUT, WOULD THERE BE A NATURAL MOVEMENT OF AIR TO RUN UP THE INSIDE OF THE DRY LINING AND INTO THE LOFT ?
THE NEXT QUESTION IS WHAT DO I MAKE THE LATHES/BATTONS OUT OF ? I WOULD BE APREHENSIVE TO USE TIMBER IN AN ENCLOSED DAMP ENVIRONMENT. I KNOW GYPROC HAVE A METAL FRAMEWORK SYSTEM, BUT WOULD THE MOISTURE CONDENSE ON THIS ? IS THERE A PLASTIC FRAMEWORK AVAILABLE ?
FINALLY, WOULD I USE AN ORDINARY BOARD, OR AN IMPERMIABLE ONE ? I AM THINKING THAT IT MAY BE BENEFICIAL WITH AN ORDINARY BOARD, THERE IS MORE CHANCE OF OF THE STRUCURE BREATHING, REDUCING CONDENSATION.
ANY HELP WOULD BE APPRECIATED

Why would you want to vent it? Not being rude just curious.

You talk about a damp envronment but give no other clue as to why that would be the case?

I would have thought that the straightforward solution is just to dot and dab ordinary plasterboard direct onto the walls and skim over.

I recently did a bathroom (damp environment) where the plaster was so rotten after stripping old tiles off that we had to completely strip the room back to bare walls and start again. What I've suggested is what we did.

A bit more detail on the general scenario might help.

Cheers

Hi Rosebery, thanks for the interest. The reason I want it vented is because I have penetrating damp from the outside wall due to render that is not perfect. I know I should try and cure the damp first, but I cant. The 1st storey wall is adjacent to a pitched garage roof and is not accesible. I have had people round and nobody wants to tackle it.
The render appears to have been sprayed at sometime by one of these vile, expensive coating systems, which I am sure is part of the problem. It has now started to break down and is holding water.
This damp problem came to light when I replastered either side of the chimney breast, with a browning base and a multi finish plaster. It just would not dry. The new plaster was sucking in the damp from the masonry.
As the render is not workable, I have just got to make the best job I can and the damp surveyor I had round suggested this is the best I can hope to do.
I hope you are now more in the picture. Cheers

A competant external render should be able to repair the external problem. It may be possible to scaffold over any external obstructions to be able to reach the problem areas.

If you still choose to dry line internally there is no need to install a ventilated dry lining, instead apply a dry lining system with an internal vapour barrier such as Oldroyd XV, Isola Platon etc.. With this system it is possible to apply an insulated plasterboard using fixings that will sandwich the membrane to the wall eliminating the need to build a stud etc.. in front of the wall.

Also, has anybody warned you about rot etc..?

If any timbers touch the damp wall, inc the floor joists and skirtings these could rot so stopping the dampness is the best way to go.