Siding question

My 50 year old house has wood shingles siding. The shingles 90% look OK, 10% is either split, broken, popped up from the house or otherwise damaged. The paint on shingles is in very bad shape is it peels everywhere. I am planning an second story addition (currently second story does not extend as far as first story) so I need to decide what to do with siding. I like wood shingles very much. What would be the best approach in my case? Remove existing shingles, and new addition is complete put new shingles on entire house? Here the problem is that the house exterior is water repellant sheetrock and shingles are nailed to studs with nails with threads. I replaced windows this summer with new construction windows and had to enlarge window opening and trim shingles. It was virtually impossible to remove shingle boards without damaging either the board or exterior sheetrock. So by removing existing shingles I am afraid of severely damaging sheetrock. It has however positive moment. I would be able to put house wrap as currently my house has none and rigid insulation on exterior walls. I am also not sure if code allows putting wood shingles on non structural surface as my water repellant sheetrock. If I decide to keep existing shingles on existing house and put new shingles on new addition I have to somehow remove peeling paint before repainting and find shingles on addition to match existing shingles on rest of the house. What's the cost of wood shingles in Central NJ?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Cedar shingles 50 yr old ? Replace them. I have Cedar shingles, took them off , put up 2" R 14.4 foamboard , 5/8 Oxb, tyvek , and the old cedar. Insulation is great but the cost was killer. Cedar only lasts so long, if it is rotting and pealing it will just get worse.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Actually the wood shingles are in great shape, they are not rotten. some just popped from the house exterior, very few are split. The paint is in bad shape. Moreover the entire neighborhood built back in 1960 is sided with wood shingles and except for paint siding looks good on all houses. The problem is that it is virtually impossible to remove existing wood shingles without damaging them or water repellant sheetrock exterior due to threaded nails used. I had to remove some this summer when I enlarged openings for new windows and half of shingles I removed broke. I also don't know where I can find matching shingles for new addition to be built.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
If it were me, I would replace the wood with cement siding. The new wood is not likely to last as long as the old wood and you will be disappointed.
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.