Damp patches on inside of gable (?) wall

FreeBear

https://www.hss.com/hire/p/treble-ladder-3-5-9-1m-t12 - Once you add in delivery & collection charges, it may make sense to buy one.

benson1980

I’ve got one of these ladders and they are good. You can obviously get different sizes and configurations to suit.

TB Davies 1102-002, Trade Double Extension Ladder, 3.3 Meter / 10.9 Feet, Extends to 5.6 Meters / 18.3 Feet, Comfort D-Shaped Rungs, 3-Year Warranty, EN131 Professional https://amzn.eu/d/9E8FRvY

Ben1989

So. Had new windows installed today which allowed me to peek out the loft window at the render below. Render was solid (surprisingly) and paint was blown. 

This new news has brought up new questions. 

1) How is the water actually getting in? Would the render underneath be that porous if paint coat has failed? 
2) Would the roof be a likely route and what would I look for?
3) I'd like to take the paint off to reveal any cracks etc. What is the best way for pebble dash? Wire brush on a drill?
4) Providing paint has been removed what is the best step process to ensure good preparation and type of paint/product to use?

stuart45

Render can be solid, not blown, and still have small cracks.
Pebbledash is best left unpainted. When some of the pebbles drop off they leave a place for water to enter and get trapped under the paint. 

Ben1989

The pebble dash is already painted and I was preparing to leave some patches where the paint was really sound. Also, with the comment of small cracks wouldn't this be best to seal?

stuart45

Once it's been painted you don't have much choice but to carry on, unless you can get all the old paint off. If people want a coloured finish the answer is Tyrolean rather than pebbledash.

FreeBear

Best way to remove paint from a wall - I'd go for a diamond cup wheel on an angle grinder. But do NOT do this from a ladder, and you must wear goggles (or face shield) and a decent dust mask. It will take the pebble dash off and create a shed load of mess that will travel (warn your neighbours and tell them to close windows).

The alternative is grit blasting, but that is going to make a mess of your nice new windows.

Ben1989

Hmmm, food for thought.

I'd rather not take the pebble dash off as I'd have to do the entire house, adding a third to the gruelling task using the diamond cup wheel. Just went on screwfix and people talking about taking concrete off haha.

I could probably protect the windows with some materials if I were to grit blast. Then going into professional territory. Loft window isn't an issue as it's high and unlikely to see imperfections.

FreeBear

You will probably find that the pebble dash will fall off as soon as you touch it with a wire brush - Mine certainly did, and the bulk of it came away from the cement base coat with just a paint scraper.

I'd suggest testing a small area near ground level just to see how bad it is. You could try a wire brush on the end of a power tools (either an angle grinder or electric drill), but will probably rip the pebbles out in the process.

Ben1989

Sure I'll test it for sure. I don't think its pebble dash as we're used to seeing. It's kind of "underneath" the render