Old siding affects how a replacement project is priced, installed, and finished. Before any new materials go up, we confirm whether the existing surface can stay or must be removed to create a flat, stable base for the next system. The only way to determine if new siding can go over old siding is through a full inspection of the current material, wall condition, and the requirements of the new siding being installed.
When Old Siding Can Stay and When it Must Go
Vinyl Usually Has to Come Down First
If you have vinyl siding and you are replacing it, we have to take it down before we side the home. We need to get back to the sheeting. Your house should have a flat substrate, such as plywood or OSB, so the new siding can be applied correctly.
This is why we do not side over existing vinyl:
- It prevents us from confirming the condition of the surface underneath.
- It keeps us from starting with a flat, clean base.
- It can hide issues that affect how the new siding performs.
Wood Lap Can Stay for Some Installs, Not All
Wood lap siding is different. If you have wood lap siding and you are going back with vinyl siding, you can often go right over that wood lap.
If you are going back with fiber cement, the requirements change. When you install Hardie siding, you have to take the wood lap down and return to a flat surface. The goal is a stable wall plane so the finished install looks clean and stays that way.
Pro Tip: This decision depends on what you have and what you are installing. The same wall can require different prep based on the new siding type.
Materials That Cannot Be Covered Reliably
Shake Siding Has Too Much Movement
If you have shake siding, which is similar to shake shingles on a roof but installed on the wall, it has to come down. There is no reliable way to side over it. The surface is too rough and has too much movement. We cannot get the new siding flat, and flatness matters for appearance and long-term performance.
In practical terms, shake siding creates:
- an uneven surface that telegraphs through new panels
- movement that works against clean fastening
- a finish that will not look straight because the base is not straight
Stucco is Always a Case-by-Case Call
We sometimes side over stucco and sometimes remove it. Stucco can be installed in different ways, and performance varies from house to house. If the stucco is performing poorly, we may need to remove it. If it is stable and conditions allow, we may be able to go over it.
Key Takeaway: Stucco is not a blanket yes or no. We have to see it to confirm the correct approach.
Need expert help deciding what to do with old siding on your home? Contact Thermal King for a free consultation.
Special Surfaces That Get Furred Out and Covered
Cinder Block Gets Built Out, Not Removed
If you have a cinder block-constructed house and you want siding over it, we do not remove the block. We fur the wall out and side over it. That creates a build-out so the new siding has a proper plane to install on.
This is a practical solution because:
- The block is not meant to be removed for a siding project.
- Furring creates a straight surface for the siding system.
- It allows the home to be sided without major structural change.
Asbestos Siding Typically Gets Covered
If you have asbestos siding, the typical path is to fur out and go over it. In most cases, asbestos siding is not removed as part of a standard siding project. This method avoids creating an unnecessary disturbance and allows us to create a new surface for the siding system.
That approach still requires planning because the build-out, materials, and process affect cost and details.
Why an Accurate Bid Requires a Full Investigation
Removal, Sheeting, and Disposal Change the Price
To give a proper bid, we have to investigate what exists and measure correctly. There are charges associated with removing siding. There can also be charges for new sheeting or other prep work if the surface is not flat or needs correction.
The total cost can change based on:
- tear-off requirements
- whether sheeting is needed to create a flat base
- How much material must be disposed of
Dumpster Delivery is Often Part of the Plan
On many jobs, there is so much debris and waste that it is not feasible to haul everything away in the back of a truck. That is why we often have a small dumpster delivered. It allows us to remove the waste efficiently and keep the site manageable.
Every home is different. The right plan depends on what is on your walls, what you are installing next, and what it takes to create a flat surface that supports a clean finished install.
If you want a clear answer on whether your current siding can stay or must be removed, schedule a quote with Thermal King today.
