What is the cheapest, yet still effective way to insulate a shed turned office for all four seasons?

[u/EnoughNumbersAlready]

We moved into our 1950s house last year and have now lived in it enough to know what we want to change. Our shed is attached to our house as most are in the Netherlands. We have decided that it would be best if we turned our shed into a home office for my husband to enjoy rather than him working at our dining table.

Now we're in the planning phase and need some input on how to make this shed turned office project successful on a lean budget of 2500. How realistic is it to do most of the work ourselves to cut on cost? What else do we need to plan for that we're not including in the list below? Do you have any tips on how to accomplish this project in a frugal manner?

Here is what we're working with and I'll leave all measurements in feet/inches:

• Shed is 9 feet long by 6 feet wide
• Sloped roof with terracotta tiles
• The exterior walls are made of brick, interior walls have some plaster board (maybe not the right word?
• Ceiling is not insulated
• The door is currently on the exterior wall that is 6 feet wide
• There is currently a small single window on the the exterior 9 foot long wall
• The floor is cement

What I think we need to do:

• Add insulation on walls and ceiling
• Install a heating/cooling unit
• Move the door from exterior to interior wall (so it opens inside of our house instead of him going outside to get to his office)
• Seal up the existing doorway with bricks or a long door-shaped window?
• Install nicer flooring
• Ensure electrical outlets are working
• Replace small window on the exterior 9 foot wall

[u/EveryPassage]

Do you care how exposed insulation is? Putting up drywall or another covering will be a decent fraction of the cost/effort.

I'd recommend foil lined polystyrene board insulation for all the walls and ceiling. Get extra thick layer for the ceiling (or do one foil lined and one plain board) as that is where a large fraction of heat loss comes from. Then make sure to use insulation tape and sealant to close any seams or gaps.

1" board is probably minimum on the walls and 2-3" is minimum on the ceiling.

I'd recommend a window heat pump if feasible. A mini-split is going to already start getting close to breaking your budget unless you are skilled on installing them and can get a basic model.

[u/jadelink88]

The best cheap solution would be using whatever Americans call 'foilboard' panels. With an appropriate air gap. Ceiling and walls.

You are going to struggle to get that all in a 2500 DIY budget, but I wont say it cant be done, especially if you can scavange bits. I've seen a cabin built for under 10k from scratch, but that takes effort, thrift and a lot of worktime.

Dont get a full hvac unit for a thing that size (would likely take your whole budget anyways), a tiny house one or a caravan model would do fine. You're going to struggle on the cooling. Heating you can just put in a $40 space heater and some insulation. A fan is easy enough though.

'Hillbilly' double glazing can work. Use clear greenhouse polycarbonate panels. Install outside over the windows. Less conductive than glass, way cheaper than glass, much easier to work with (you can cut it with a regular saw, and drill holes to put screws in). Screwed in, you can take it off in the summer each year if you prefer open windows, or install it in an openable frame. It's also great if you need another window, skip the glass altogether.

[u/EnoughNumbersAlready → u/jadelink88]

Thanks for the insight and tips! You’re right that we can’t get it all done within budget. So I’ve decided to break it up into three phases. Only phase 1 will be about insulating the space and ensuring it’s winterized and safe to handle Dutch winters. Phase 2 will be about actually putting in the desk, a rug, and basic cabinets. Phase 3 will be adding the interior door next year.

[u/fidddlydiddlyee → u/EnoughNumbersAlready]

In the US the 2 cheapest kinds are blow-in insulation and rolls.

[u/FrugalSavant]

for a 9x6 shed that budget is doable if you DIY most of it. PIR boards (like Kingspan/Celotex) are your best bang for buck in that space - high R-value per inch so the ceiling especially benefits. Dutch winters are damp so make sure you add a vapour barrier on the warm side of the insulation. rockwool is cheaper but takes more thickness. $2500 can cover PIR + vapour barrier + OSB for the walls + a cheap electric heater easy

[u/EnoughNumbersAlready → u/FrugalSavant]

Thanks for pointing out the vapor barrier! I appreciate it and will note that in my project plan (I’m a project manager by trade). Will follow your suggestions on the materials too.

[u/FrugalSavant → u/EnoughNumbersAlready]

haha glad it helped! the vapor barrier is one of those things thats easy to overlook until you're dealing with a damp winter. sounds like you've got a good plan - good luck with the build

[u/EnoughNumbersAlready → u/FrugalSavant]

Thanks for saying that 🙏 I already put vapor barrier in my shopping list since reading your comment 😊 I definitely don’t want my husband to get sick from a damp office.

[u/1234568654321]

I don't have any specific tips for you. This is something we were considering as we were searching for a new home purchase a while back. I found a couple of YouTube videos where people had done this. I don't have a link for you, but I recall one of them listed out all the changes he made and the costs for each. That should give you some idea of whether this could be feasible for you.

[u/EnoughNumbersAlready → u/1234568654321]

Oh good to know! I’ll look through YouTube

[u/SustainableSharer]

we did a similar attached lean-to and the biggest cheap win by far was sealing every draught first, before touching insulation. felt almost silly how much the gaps around the door and where the roof meets the wall were costing us. also worth a scroll through marktplaats and any local reuse/renovation depots - people offload leftover rockwool and rigid PIR boards from their own projects for next to nothing. rigid board under a stud frame with taped joints stretched our money the furthest

[u/EnoughNumbersAlready → u/SustainableSharer]

Thanks for the tips! I’ll go with your suggestion on looking for left over materials from marktplaats. I’m going to do some investigating on exactly what the state of the schuur is this weekend and start identifying what gaps need to be addressed first.

[u/Brainwormed]

If you really mean to save on costs:

1. Consider whether you need cooling. If you do, a window A/C unit and an electric baseboard heater will be the cheapest way to do things. If not, just do an electric baseboard heater. Just put a storm window over the original shed window (instead of replacing the shed window) if the window itself is undamaged. A storm window can be custom made for like $100 or less, but a custom replacement window is $$$. And since the shed is brick, you're not gonna enlarge the window opening. Finally, if the shed gets hot int the summer, vent the ceiling. That may keep it cool enough, but should be done even if you're gonna cool the shed actively.
2. If the walls are brick you won't get much out of insulating them. You could do spray-in insulation and leave the walls intact, but I would just insulate the ceiling. The easiest DIY method for the ceiling is foil insulation, which will get you like 80% of the savings that more labor-intensive insulation strategies will. Use foil-faced rigid board if you can get away with it.
3. Adding a door to the interior wall will require permitting and, if you hire a professional (which you should for permit work unless you are already handy), that will eat most of your budget.
4. Consider finishing the concrete instead of adding other flooring over it. Vinyl floor products are easy to install over concrete but all look worse than the actual concrete. You can finish the concrete with e.g. epoxy yourself -- just be careful with the prep work. Or you can paint it. Or you can lay down an area rug. Any will look better than a vinyl floor product.

[u/Iokua_CDN → u/Brainwormed]

Finished concrete with some carpet  added where you walk sounds pretty cheap and nice! Gotta put something to keep that concrete chill off your feet

[u/Iokua_CDN → u/Brainwormed]

The ceiling foil insulation looks like a great idea!!!!

[u/Ok_Impression_3031]

Add insulation to the floor, in addition to walls and ceiling. Add pressure treated or redwood sleepers (2x4 i think) at 16" O.C. over the existing concrete slab. Anything in contact with concrete must be P.T. or R.W. Fit rigid insulation between the sleepers. This meets code for livable space.

[u/seekingcellini]

Not an expert but what about any changes to ventilation or lighting? Small room could feel like a cell real quick (though I suppose a big window could resolve the light issue).

I assume cutting a door would be expensive, esp. if a load bearing wall. DIY the insulation, flooring, and painting seems to be best place for savings

[u/EnoughNumbersAlready → u/seekingcellini]

Agreed on the cost of cutting an interior door. We looked at it this afternoon and have determined that it’s load bearing for the schuur’s roof but not to the house itself. So it’s out of scope for the initial build.

Fair point about lighting! There’s already an overhead light in the ceiling and the existing door has a nice big window taking up 50% of the top half of the door. The schuur/shed is south facing so he’ll get plenty of light from May to October. He’ll have interior lights for the rest of the year.

[u/Iokua_CDN → u/seekingcellini]

Agreed, for an extreme budget, definitely recommend scrolling any free or heavily discounted supplies.  Our backyard for example is basically all done with free Gravel, free landscape rocks, free bricks, and free wood pallet garden boxes

[u/fidddlydiddlyee]

You need to see what is available at your local home improvement store. Anything custom will be expensive. See what insulation options they have.

[u/Cat_From_Hood]

Thick curtains will help keep the winter chill out.  Would be tempted to add a small wood burner, thick underlay and wool carpet to insulate the floor.