How to Find the Right Replacement Windows in Ireland

If you need to brush up on the basics of replacing a window, I refer you to the plethora of excellent information on that subject available everywhere from the library to the internet to home depot. In this article I’m going to tell you what to do if you can’t find replacement windows of the right size, and you’re on a very limited budget (as many of us are these days).


So to return to our narrative: You whip out your tape measure, prop the sash open with a stick (or better yet take both sashes out) and get the R.O. (rough opening) size for the window. You get some strange size like: a 28 inch width, by a 66 inch height, or a 40 inch width by a 48 inch height. You go down to Home Depot or Lowe’s and you can’t find anything that comes close, even within a few inches. What do you do?

Well, there is the obvious solution – go to the pro desk, give them the rough opening dimensions that you measured, and ask them to order a custom sized window for you. Just in case you didn’t know, the standard sorts of vinyl windows Ireland you find at popular home centers and window dealerships can be custom built to virtually any size and shipped to your local store or even your home.

The trouble is, of course, that this costs more. It can run you as much as 100 dollars extra. In addition, you’ll have to wait 2 weeks to a month before you can even get started. I’m assuming a worst case scenario here – you’re close to broke: you’re not about to pay somebody else to put your windows in, and the thought of shelling out an extra hundred dollars even to have one custom ordered is a real bummer at the moment. Let’s say time is also a factor: the muntins are so crumbled that the ancient window putty falls out when you even walk by, and rain or snow, not to mention cold air, is getting in. 3 weeks is not a realistic time frame. You’ve got to fix this, like, today. So what can you do?

We’ll use the logic of an old saying here: “If Mohammed won’t come to the mountain, take the mountain to Mohammed.” Translated to your present day situation: If you can’t find a window the right size for the opening, make the opening the right size for the window. If you’re fairly inexperienced in household DIY projects, this may have briefly occurred to you, but you dismissed it because it was a “construction project” rather than a simple replacement job. However, this is not such a difficult job, and if you’re a bit enterprising you can probably tackle it yourself. Let’s face it, it’s better than going on the way you’ve been going: eating breakfast in the arctic or the rainforest, and sweeping up crumbled artifacts from a bygone era from your floor, and never being able to open the window up to let fresh air and unobstructed sunlight into the room (for fear the window will fall apart).

First let’s talk a little about how a house is constructed. A house has a kind of “skeleton” known as the frame. On to this skeleton are added all the parts of the house that you generally see or that make it livable: the roof, the drywall, the decking and siding, the plumbing and electricity, the windows and doors, and so on. In the case of windows and doors, there are square or rectangular gaps left in the frame to accommodate them. In older houses the frame may be composed of different types of lumber than 2 by 4s, but the idea is the same. On to these framing members as the lumber used into the frame are called, the window – basically composed of jams, moldings, stops, sill, and sashes – are placed.

Now, when you’re doing a simple window replacement, 95% of the time you’re not even dealing with the frame. You usually simply take out the sashes (the parts of the windows that slide up and down or open) and put the replacement window into the open that’s left. Replacement windows Ireland are, in fact, designed to be narrower and smaller than the original window that was used in the construction of the house, both so that they fit into this opening length and width wise, and also as far as breadth. In other words, they are more or less the breadth and size of the sashes and not the original window itself.

This, then, is what you’re dealing with too. Unless you want to rip out all the rest of the parts of the old window and open up the wall to reframe the original opening, which I wouldn’t recommend for a beginner, especially not in your situation, you need to make adjustment to the rough opening that is there when you take the sashes out.

Here, in list form, is what you can do:

1. Find the window at the store you’re at which is closest in size but smaller than the opening. It must be smaller rather than bigger than the opening, because if you get into making the opening bigger, you’ll have to make adjustments to the frame itself, and as we’ve said you don’t want to do that.

2. Wait for a time when it’s not too rainy and cold and take the sashes out. Now you’ll have the opening we’re talking about – the R.O. formed by the jams (which are the vertical side pieces), the head (which is the horizontal top piece), and the sill (which is the base piece). Often the sill will also have a piece the projects from the wall, the classic “window sill” you see when the window is all together. You probably will not need to rip this out, so leave it alone.

3. Now what you want is to get the breadth (the depth) of the jams – head – sill lumber that was used. That is, not the length or the thickness but the width as it spans away from you from the inside to the outside of the house.

4. If the window is especially tall you may only be able to find shorter windows. This, in fact, is a common scenario. In the past, windows in Ireland were often taller than the common sizes in the present day. So we’ll use that as our example.

5. Let’s say you found a window that fits the R.O. width well enough but is, say 10 inches shorter than the height. You’ve got an R.O. height of 66, say, and the replacement window is 56. [Note – the replacement window can be slimmer than the standard 1/8 width on each side and still need no adjustment for the width. There can be as much as a ½ to 1 inch gap on either side. As long as it will screw into the jams on either side you can stuff a little insulation in the air space between the replacement window and the jams, and cover it over with molding. More on this shortly. What you need to do is build down from the top. So you need to match as closely as possible the jam dimensions.

6. Often the jams are around 5 ½ inches, because this is what the actual measurement of 1×6 or 2×6 lumber measures, which is a common width for jams. The older the house, the less standard the lumber sizes become though, usually. So you may encounter jams of 4 inches of 5 inches.

7. You will need to put fairly string wood in the 10 inch space that is left on the top of the window because it in fact, needs to be a new framing member. You’ll be nailing drywall or whatever you use for sheathing to it, and the window will also screw into it on top. So it needs to be strong, not merely a piece of wood. So: get 2x lumber that is either the exact width of the jams or wider. i.e. if the jams measure 5 inches, get regular 2×6 (which will be 5 ½ ).

8. If it’s the old jam is the right size, i.e. 5 ½, you don’t need to make any adjustments to its width. If however it’s thinner, rip the piece of wood down with a table saw or circular saw to the exact width of the jams. Now you’re ready to put what amounts to a new frame, onto which you can nail drywall and into which you can screw the replacement window on top, into the extra space you need to “fill up.”

9. Screw or toenail in a header across the top. This should be around 1 inch higher, measuring from the sill, than the replacement window height. Replacement windows come with “head expanders” which can be adjusted to fill this space at the top, and having room up there will allow you to put the window in easily.

10. In the original framing of a house, the jam boards are thinner more decorative (fine grained) boards put on top of the framing members e.g. 1×6 nailed on to 2x4s. Note that there usually isn’t necessarily a reason to add a piece of 1×6 on to the piece of 2×6 here unless you care that the wood is more fine-grained or decorative looking. If you do care about that, simply get a piece of 1×6 decorative lumber and rip it down to the same size (if necessary) as the 2×6, place the 2×6 framing ¾ of an inch higher than you would have otherwise (i.e. if you only used the 2×6), and then you can nail the piece of 1×6 flush on to it with finish nails.

11. Measure along the header (or header/decorative jamb) you’ve screwed in to get the length. Divide this by either 2 or 3 (depending on how many vertical pieces you want to put in) and measure and mark those locations on the new and old headers. Also measure the height from the header you’ve put in to the old head at the top. Now cut new pieces of the 2×6 or ripped lumber at this length and screw or toenail them in vertically between between the new header and the old header at the marks you made.

12. Voila – now you’ve got a new frame/R.O. Try your window in the opening to make sure it fits. Again there should be about ½ to 1 inch of space on top that can be filled by the head expander.

13. Cover the framed in space on the top of the window with drywall, measured to its size and screwed or nailed in with drywall nails. Often old houses have plaster and lath as the inner wall sheathing/finish. Try to match the thickness of this as closely as you can with the drywall. i.e. if it is around ½ inch thick, buy ½ inch drywall, etc.

14. Caulk around the rear stop to create a seal when you put the window in.

15. Now place the replacement window into the opening, press it so it’s tight against the stop, and screw it in on the bottom, top, and sides, as indicated in the instructions. Try the window to make sure it opens and closes well. If there are problems or rubs, they can usually be cleared up by adjusting the tightness of the screws that you’ve used to screw in the window.

16. Paint the drywall with paint that you’ve matched to the color of the walls.

17. The only other thing you have to worry about is the molding. Using a miter saw, you can take the pieces of molding off and, maintaining the same angles, cut the two side casing pieces down to the new size. The top piece will stay the same, unless you have to cover up space on the sides of the window as mentioned, in which case the shorter width (the “bottom of the angle”) of the top piece has to match the width of the replacement window, and the side moldings have to, of course junction with it. Again, simply stuff fiberglass insulation into the spaces on the sides of the window if any, or spray in foam insulation, which you can buy in easy to use spray cans.

18. This latter method is easy, but can be messy. When you’ve got the molding/casing to the right dimensions, nail it in with finish nails. You have to nail it into wood of course, not anywhere on the vinyl window.

19. If the window is significantly thinner on the sides – less than 1 inch on either sides – you will need to build it in, in much the same way you built down from the top. This will usually take the form of putting 1×6, 2×6 or ripped 1x or 2x boards directly up against the old jams to build them out.

20. You may even wish to do both – build from the top down and the sides in. If so I recommend building the top framing first and then building in from the sides. This will economize on wood and generally be more straightforward.

There can, in fact, be a number of different scenarios when creating a new R.O. to fit the size windows you have, but they almost all follow this overall pattern. This should give you a sense of what is involved. These kinds DIY projects, while possibly seeming more involved than what you have experience for, can be an interesting and rewarding experience and are usually not as difficult as they seem. Good luck!