Home Improvement--General/facia paint staining


I have recently replace all my facia boards around my house using shera board (concrete based) , sealed and painted correctly.
But the problem I am having is  that when it rains the water flows back up under the tiles in places and down onto the facia's. which has now left a dark stain where the water comes off the roof tiles onto the facia boards.
(where the facias get wet from direct rain there is no problem)
It is not a fungas, I have tried removing the stains with citric acid, hi pressure water cleaner and neither works.
Can yougive me some ideasas to how I can stop the staining or water running back under the tiles.
P.S. the roof has a reasonably steep pitch.


You are right, the roof has enough pitch that water should not be backing up under the tiles.  I don't know a lot about shera tiles but I can offer a few ideas that may be useful.  Most roofs here have a felt underlayment before the finished roofing material is applied.  That underlayment is tar impregnated felt which will bleed if it gets wet.  I don't know if the same practice is followed where you are, but when that bleeding occurs a black stain develops and it is very hard to remove.  It often requires sanding and repainting.  The tiles are surely not causing the stains but was some type of mastic used to attach the tiles; most mastics have tar type bases.  The other possible culprit might be whatever sheathing was used which may have some ingredient that bleeds out when it gets wet.  The important point, however, is why is the rain backing up since there appears to be more than enough pitch (looks about a 6/12 or more).

The stain must be coming from one of the components so I would look at each to see what they are made of and do they have an ingredient that is the source.  I would also get the manufacturers product spec sheet and installation instructions to be sure everything was done as instructed and to see if any cautions were noted in the specs that might lead to what is happening.  Here is a good cleaning solution for stains on wood: 6oz. TSP, 2oz. Tide, 2qt. bleach, 6qt. warm water.  Botttom line is you need to find out why rain is backing up under the tiles unless you are having hurricane level winds.  Good luck, sorry I couldn't be of more help.

Len Kroll  

Home Improvement--General

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Len Kroll


I can provide advice on the proper design, construction, maintenance, restoration, preservation, cleaning and waterproofing of log homes. Questions concerning proper cleaning, sealing, staining and waterproofing are within my area of expertise. My expertise includes new construction and existing log structures. Chinking application or restoration, log replacement and repair are also in my area of expertise.


40 years experience in the log home and construction industries, 10 years in specialty contracting, 30 years in the log home field. We have designed, produced, supplied and built over 3,000 log homes and restored/repaired over 600 log homes. See more information at our web site: www.woodhouseloghomes.com.

Authored a monthly column expressing the Vice President and General Manager's "Observations and Insights" distributed to 300 employees and management.

BS degree in accounting, University of Illinois, 1963. Master of Business Administration degree, University of Chicago Graduate School of Business. Numerous relevant seminars including an intense two week business administration seminar, University of Pennsylvania Wharton School of Business, 1978. National Home Builders Association Graduate Builders education program.

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National Honor Society Student, Illinois State Academic Scholarship, Dean's List.

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