I absoulutly concur with Dan S. Even to just remove the discoloration, you will be removing old stain and will give it the appearance of being uneven. Do do it properly...Strip it, caulk it and re-seal it. This is only the true way to bring it back.

Being a ranch style house...you are not looking at a lot of monies to have this done. Consider getting bids on the restoration and having it done properly. If the weather is right, you can have this done in three days. 1 DAY WASH AND THIRD DAY CAULKED/STAINED. For a professional..you are looking probably around $1700-$2300 to have this done but well worth it. Especially if you are trying to sell.

Just my 2 cents worth.

One Call Power Wash & Fleet Service
www.onecallpowerwash.com