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Removal of lime morter and applying polyurethane spray foam to slate.

My property is over 100 years old with a slate tiled roof and some of the lime morter is dropping off the slates or is loose and will drop off if touched. Is Polyurethane spray foam safe to apply direct onto slates from the inside as I understand it expands? Does it damage the slates and dislodge them? What, if it is safe to do, substance can I use to remove any lime mortar that remains?

2 Answers from MyBuilder Roofers

under no circumstances what so ever apply foam to your roof,it seals everything in stops your roof breathing and will rot your timbers any slates will be unusable as you cannot get it of the slate, you can have the lime mortar along the lathes replaced,which is a more realistic solution to foam BUT BASICALLY IF THE ROOF IS NOT LEAKING DONT DO ANYTHING.

good luck


Answered 10th Oct 2012

As above.


Answered 11th Oct 2012

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