removing dark mold on outside of house

We have a 100 year old victorian with wood on the outside. The north and south side have patches of dark mold growing (looks like dirt) which I removed with a bleach solution a few months ago. Now more is appearing on these sides of house. Any suggestions? Do I need to have the entire sides washed with bleach solution? Will this be an annual ritual?
thanks,
John
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
you could always try T.S.P (tri-sodium-phosphate). it works pretty darn well as a cleaner, i use it all the time on my deck, concrete, etc...
home depot has premixed T.S.P that really does the trick IMHO.
good luck
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Try a stronger bleach mix, spray twice letting it dry then wash it off with Tsp, But with the right environment it can come back. There are anti mold additives for paint
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

On my house I used spray bleach, worked great. Rinsed with nozzle on hose, afterwards. Mold/mildew may signify leakage problems along wall, or thru roof, especially if the stuff returns. Once I re-roofed, repaired gutters, and improved perimeter drainage, the mold never returned.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.