We are purchasing a home and have two rooms we would like to improve the window situation in.

In the dining room we would like to replace the regular 36x54 double hung with a 48" round picture window, and then move the old window (or possibly get a new casement window) to the adjacent wall which currently has no windows.

The living room has only a pair of similar double hungs in the corner and then about 9 empty feet of wall between those and the sliding door to the deck. We'd like to take out those windows and have something like a large 1/3 sash sliding window as big as we can afford/is feasible up to 120x60. If that's too crazy then maybe 3-4 narrower tall windows, we just want as much view as possible because the ceilings are low and the view is great (private backyard sloping down to parkland/creek).

Even our dream windows aren't bad in terms of cost. I understand the work will be extremely expensive because of need for support, headers, structural engineers, permitting, all that (outside is just vinyl siding and I don't think there is plumbing or ductwork in these locations). What I can't seem to get answers on is even a general idea of how expensive, because none of the general contractors I've been contacting will tell me.

Some just said "We can't be of service" which I thought was weird because their sites listed everything from "small projects" and basement/kitchen remodels to building of additions or complete homes. One said they can't tell me anything without structural drawings from an architect or engineer first which seems backward to me (I contacted the architect they referred me to, and they said it would be about 20 hours at $200/hr just for the drawings). I had thought the process would be I'd talk to a general contractor about what I want, he'd assess the situation and give me an idea of price, then he'd take care of getting the structural engineer to do the drawings etc. I can't seem to get to step 1.

Contractors on reddit said this would be expensive but also that it isn't really rocket science and an experienced GC should be able to give me an estimate without opening up the wall etc (we don't close on the house for awhile but I'm trying to figure reno/repair budget).

Can anyone give me an idea of what to expect or at least tell me what kind of contractors I should be calling? I mean I know it's not super common to add windows but it's also not rare and I assume most people aren't paying $6k to get a drawing before they can even talk to a contractor about doing the work lol

  • 2
    Considering that a basic pocket window replacement goes for $1,000, would you scoff at a quote of $20,000-$30,000? It sounds like you have a very particular vision in mind and contractors will see that as a red flag unless you offer a budget before requesting the quote. You probably shouldn't be talking to a GC anyways; reach out to an actual window installation company.
    – MonkeyZeus
    Commented May 10 at 16:55
  • 6
    Um, way to bury the lede. You don’t own the house yet. Of course contractors are going to give you the brush off. Close on the house; give them access. Expect a wild ass guess to be free, but expect to pay for anything remotely anchored in reality. Commented May 10 at 16:59
  • Going in we assumed we would be paying about 20k for both rooms and as I said can adjust our improvements as needed - worst case (cheapest) scenario is just the swap of the old window for round window in the dining room, and adding another conjoined pair of regular double hungs in the living room. Although 20k does sound high for that less desirable outcome. My understanding was window installation companies didn't do jobs like this, only fairly basic swap-outs of old windows for new windows? Everything I had read indicated a GC was the right person for this.
    – PrestonJoe
    Commented May 10 at 17:00
  • @PrestonJoe In my area, Comfort Windows is quite popular and they provide a full range of services so your project seems right up their alley.
    – MonkeyZeus
    Commented May 10 at 17:05
  • 2
    As for "Even our dream windows aren't bad in terms of cost." I sincerely hope you don't communicate this mindset ahead of time because it's also a red flag. You're contacting professionals to come in and do what you are unable to achieve so if you hint something like "it should cost XYZ in my mind" then that's why they're ghosting you.
    – MonkeyZeus
    Commented May 10 at 17:11

3 Answers 3


I understand in some areas, a window company may do this type of modification. However in most cases you will need a General contractor because changes will be made to the structure. Because of those changes a set of drawings will be required by the governing building department. Only then can a GC perform the work.

The process for getting the drawings can be expensive, as you have discovered. First the engineering firm must come to the home and take measurements and do a general assessment of the type of construction that you have. Then they must do their calculations based on what they believe should be in your walls. Drawings and instructions are made based on that and other information.

Your GC will have to plan their work, ( and subsequent price) on the drawings along with planned cost for demolition, debris removal and a contingency for what may "popup" because something always does.

It is tricky for a GC to do estimates for these type of jobs. You are not a complete renovation, nor are you a simple window replacement.

I suspect this is why you are finding it is a tough time getting an estimate. You wiil have to wait until the home is yours, then, If you are up to it, you may consider doing some demo yourself. In the interior, remove the drywall or whatever covering you have on your walls, from floor to ceiling in all the areas where you want to place windows and remove windows. This exposes things and reveals some of the unknown. What may need to be done is then more easier to discern. Then ask a GC for an estimate. A good one should be able to give you a range to consider.


You are crossing the lines of abilities with this type of project. You need four things.

  1. Architect/engineer to OK the installation of the windows and appropriate framing for them.
  2. Person to do said framing.
  3. Person to measure/make the windows and install them.
  4. Person to fix the siding/outside of the house.

(then you need #5 or #2 to come back out and finish up the interior drywall and trim)

I am a very fair person and sometimes take on projects like this. But I work as a GC for myself or people I know well. I might tell someone that I make 2-4k plus costs (I would do 2&5).

Generally GCs (general contractors) will not do this type of work. Why? Because this is basically what window companies do.

If we are fixing up a home and need windows, change windows, whatever like that... we are gutting the inside to add framing, headers, whatever. Then we either buy stock windows (which is easy because we are framing) and sometimes have to have a window company come out. We generally don't do new windows unless we are changing the siding on the house. So the steps are normally:

  1. Demo
  2. Architect if we are taking out structural headers.
  3. City sign off.
  4. Frame new stuff.
  5. City inspection.
  6. Install new windows or hire window company. (we surely don't custom order windows and install them - this is dumb for many reasons)
  7. If your changes are drastic window company might have ideas to trim the outside windows without needing new siding. If not we are hiring a siding company for major repairs or more likely new siding. And then why would we pay a siding company 3k to fix up for new windows vs 6-7k for new siding (rhetorical question)?
  8. While outside is getting done we are insulating, drywall, trim.

So you see even though I can act as a GC I am hiring a window company and siding company and these are not subs of mine (they could be for very large home renovation companies and my crew can do certain types of siding). So if my main job as a GC for your project is to demo, frame, repair inside... Why would I give you a quote dependent on architect, window world, and siding company? Why would I want to come out to your house and deal with all of their mess ups - do I get paid extra for that?

In my area (large city) there are a handful of large "home renovation" companies that can handle this project. They will manage everything and you will pay maybe 100% the sub costs. So if architect/window/siding is 20k, the home renovation places will charge 20k more to manage (at least).

  • #5 seems to be missing; it's also referred to in "I would do 2&5". Commented May 11 at 16:29

Adding to the other answers. My experience is that the job is too big for a handyman and too small and fiddly for a builder.

Modifications can be more expensive than New structures. Without knowing what the structure is, genuine contractors aren't going to give you a price.

Try asking for recommendations from a window manufacturer.

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