Vinyl Siding over old siding

I am in process of buying a house which has old sidings. (See pictures). We are going to install new windows (all) and new vinyl sidings and possibly roof. In past i have taken out old sidings and install new vinyl sidings. tyvek and insulation on top of tyvek and then insulation. But i am thinking something differently to add the R value .

1. Can i install the new vinyl siding on top of old siding. basically tyvek on top of old insulation and then foam board insulation 1/2" and then vinyl sidings.
2. In past i installed new windows and then did sidings. But now it will add some thickness so what should i consider while installing windows before sidings for additional thickness without compromising any look and it has to look even.

 

1. Almost anything "can" be done but that method is almost never done. The thickness buildup of all those layers will really drive the cost up as you have to do special trimming around all the windows, doors and all trim work. Just look at everything on the exterior of your house and see what affect adding another inch+ of siding will do. Personally I would not go that route. Remove the old siding so you your new siding can have better attachment and you're not dealing with so much siding thickness.

2. You will have to pick your windows accordingly. Standard windows are not designed to accommodate so much thickness beyond the exterior wall sheeting. So, you will need to find a window designed for what you want to do or you'll have to modify them or their trim yourself.

 

Building your gable end walls out could pose a challenge with the fascia board [lack of overhang]

 

Tear it off. Not much else to add to whats been said. You might think leaving it on saves work but it doesnt. It makes more work.

 

Thanks guys. I have decided to take it off from the suggestions. I guess its just have to keep aside some cost for renting the trash container.

 

I can't tell from your picture but if your old siding is aluminum it can be sold as scrap which will greatly reduce what you have to pay to throw away.