How To Build A Man Cave On A Budget

By The Garden Room Guy | Build

If you want to know how to build a man cave on a budget, discover our Featured Build by Angus McGregor, who built his own Man Cave using mostly salvaged and second hand materials. 


Angus has a fairly typical UK garden, reasonably compact and surrounded on all sides. His first task was to decide where he wanted to site his man cave. In his case, this was the very rear of the garden. This obviously meant that a sacrifice was needed… his beloved – if not beat-up – shed.

But before you shed a tear for him (sorry!), don’t worry – he’s designed his man cave so that it can accommodate all of his shed-gear in it, with a separate room dedicated to his tools! If he had the space he could even turn his shed-section into a Shednasium by adding a few bits of gym equipment, like this one which I built myself.

With the space cleared, it has revealed some things which needed attention – namely the damaged/rotten fence panels/posts. So he replaced these and made sure everything was good to go – because once the new man cave goes up, it’s going to be hard to access these areas.

He also gave the nearby bushes/trees a thorough trimming back prior to construction.


With the site prepped, he turned his attention to the ground works. Firstly, using some string and wooden pegs he measured out the floor area of the man cave, and then dug down and made sure the site was completely level.

He then placed down reclaimed concrete blocks into the correct positions, at regular distance intervals, to form the footings of the man cave. With a spirit level and a long piece of wood he ensured that they were all at the same heigh as each other before proceeding.

With the block footings now in place, he laid down a weed protection membrane, to stop any plans from growing up underneath his man cave.

Next, he’s got a bunch of 6×3 inch railway sleepers, and laid them across the concrete blocks, making sure they’re all level. You’ll notice that the sleepers have been treated with a wood preservative to protect them from water ingress (rotting) and fungal decay.

With the sleepers in place and protected from the elements, next up was the man cave floor sub frame. But before this, Angus has placed a damp proof membrane between the sleepers and the sub frame, to further protect the floor structure of the man cave from moisture penetration.



You’ll notice that these sub frame beams (4x2inch) have grey paint on some of them – these again were leftover scraps of wood, salvaged from a building site (with permission of course!).

The next step was to insulate the floor. This was done with 100mm thick Celotex PIR insulation boards. Each board comes in an 8x4ft sheet (2400x1200mm), is cut down to snugly fit each gap within the floor. Any gaps are sealed with aluminium insulation tape.

With the floor insulation complete, next up was to cover with some reclaimed OSB (Oriented strain board) sheeting, which is itself recycled wood shavings which have been mechanically compacted together with a resin to form a very strong sheet material.

With the floor of the man cave complete, Angus then turned his attention to the walls, starting with the rear framing.



The wall frame has been made using 100x47mm framing timber. It was constructed in sections on the ground and is then stood up ready to be attached in place.

It makes sens to build all of the walls before attaching them to the base, as this way, you can use the base of the man cave as a giant ‘work bench’. If you’d attached each wall as you went – if you’re site is small – you’d probably struggle to find a good space to build the walls ensuring they are all square and level.

In this photo you can see that Angus has began attaching some more reclaimed OSB sheets to the outside of the frames.

The next thing needed was the breathable membrane on the outside of the OSB board which would provide breathability to the man cave, but not allow moisture to pass through and rot the wood.

Some wood battons where then affixed, which would be used to attach the final finish wood cladding.

In Angus’s case, he chose to use tongue and groove cladding on the outside of his man cave.

Next, up go the walls. The side walls have a bit of space down the side of them so Angus has chosen to leave the cladding until once the walls are up on these.

He’s just used extra lengths of the 100x47mm timber as a brace to hold each wall in place until it is permanently fixed into place.

Now all of the walls can be affixed in place and the main door can be installed. Again, the door is a second hand item (along with all of the windows) which was purchased from Ebay.

With all of the walls in place, the roof joists are then added. Depending on the size of your man cave, the sizes may need to vary – but Angus has gone with 150mm x 47mm joists.

The next job was to cover the roof joists with a layer of plywood, on top of which will go the insulation slabs.

Angus has created a 100mm ‘lip’ on top of the roof (using 100mm x 20mm planks), which will be in-filled with the insulation slabs. You’ll be able to see this better shortly… but before that, on goes the final recycled OSB sheets onto the outside of the timber frame walls.

Next is the additional reclaimed door to the right which has been fixed into place.

A breather membrane has now been applied and batons attached to the outside, ready for cladding.

Maple cladding has been used for the front of the man cave, as it has a great aesthetic, however – in Angus’ case – where the sides and rear of the man cave are not going to be seen, a cheaper alternative can be used. When creating your own man cave, remember if you’re unlikely to be able to access the sides/rear of it, then you should probably give the wood a very good quality weather proof treatment, as well as using proper pre-treated exterior grade wood.



With the walls complete, Angus turned his attention to the roof. On top of the plywood sheets he’s used 100mm Celotex slabs again.

And then covered the entire roof with 12mm OSB sheets, fastened along the edges using wood screws. 150mm long screws are then used, which go all the way through the insulation slabs and affix into the plywood and joists below, ensuring he’s drilled in the screws in the correct places, directly underneath a joist (he’d marked where every joist was on the OSB board).

With the roof now secure, he’s then laid down the EPDM rubber roof material, which brushed over to remove any lumps & bumps, and then glued into place using specialist adhesive.

The rubber EPDM material is folded over the ends of the roof and secured in place with a length of plastic and screwed down. The plastic has a lip on it so that rain water will drip off of it and into the plastic guttering which is placed at the rear of the man cave.



The next decision Angus had to make was how to channel the water which is collected by the gutter? He decided to run a drainage pipe from the man cave, down underground and dug a large hole where the water can naturally drain off into the surrounding soil.  This is what’s known as a Soakaway drain or a basic French drain.

In this case, Angus has used a plastic bottle crate to place inside the hole, in order to create a sturdy void inside the ground which can fill with water as necessary in a heavy downpour. It;s worth noting that there could be issues with plant growth above one of these buried drains, however typical lawn grass should be fine.

The crate has been buried so that there can be at least 8 inches of soil above it, enough for a lawn to still grow healthily above.

With the crate buried to a sufficient depth, Angus has then covered it over with some weed control matting material to prevent the soil from sinking through into the void.



Next up on the list is the man cave’s front decking. Firstly some footings were laid for the framing. These are simple high-density concrete blocks, which have been levelled and set in some concrete mix.

The framing of the decking has then been made, using 150mm x 47mm treated timber lengths.

Here’s the decking, as seen from the front of the man cave. You can see that Angus has extending the decking around the sides of the man cave slightly. This will make it look a lot nicer once the decking boards are down.



So here is the exterior fully finished – and I think it looks great!

Personally, i’m not hugely keen on the colour and style mis-match of the cladding, and doors, however when on a tight budget you have to make do with what you can. Plus, a tin of paint could do wonders to improve the colour-coding, if it bother you that much. All small things, and when you’re figuring out how to build a man cave on a budget, you have to go with what you can find and scavenge and make the most of it. Angus certain has done that!

But before we get too excited, we haven’t seen what Angus has done to the inside yet – and there’s still quite a bit of work left to go to make the man cave habitable.



With the outside of the man cave now pretty much water tight, Angus then moved inside to tackle the interior. The first job was to insulate all of the walls. This was done with Rockwool insulation material.

Whilst doing the insulation, it is also important to route any electrical cables which will be hidden behind the walls. Angus has drilled holes through the joists and studwork to enable the wires to be fed through.

With the wiring routed and all of the insulation in, Angus has then insualled a vapour barrier which will keep any moisture which is inside the man cave from getting to the wood/insulation and cause it to rot.

Angus then wanted to put up a partitioning wall inside the man cave so that he could separate the space  in two – one for a work space and the other as storage.

This was created using the same 100mmx47mm framing wood used to construct the walls. With the partition up, Angus could then begin plaster boarding the entire inside of the man cave.

Once all of the walls were fully plaster-boarded, Angus gave them all a few coats of white paint. It’s worth nothing that most people would then get in a plasterer to skim the walls so that have a super smooth finish. However, to save money and time, it’s also possible to buy tapered plasterboard, which essentially allows you to just use some filler to fill the joints of each plasterboard – and the final effect is the same as plastering, but without having to pay for a plasterer.

Next up was to lay a final sheet of insulation material before installing the reclaimed wooden flooring.

With the flooring complete, it’s now time to turn to decoration!



Angus has done an amazing job with this – it looks so classy, and the fact he has used recycled materials to create such a look is a real inspiration for those looking how to build a man cave on a budget.

The interior has some great touches, and I especially like the lighting – those coloured cables and the wire frames around them look great! I found these Retro style coloured metal cage ceiling pendant light shades below on Amazon, which are similar and would also look great too. They’re



The man cave at night…

You can see the full video of Angus’s man cave build here.

About the Author

I'm the Garden Room Guy. Or as most people know me, Sef. I started this blog to document my own garden room project. If it helps you at all, please let me know! Sef

  • james says:

    Awesome blog. Do you have any plans on how you constructed the base / sides etc as I’m wanting to build one 3mx5m and would love to get an idea of spacing for frame/bracing etc.

  • Ben says:

    Inspiring stuff. I’m going to build myself one of these.

  • […] If you want an idea of what these look like in practice, check out some details (and see interior pics) on the Garden Room Guy site. […]

  • Martin says:

    Really interesting read, I’m thinking of building a garden outhouse which is not square, 16ft across the rear wall, 10ft deep, 10ft across the front and the final wall will be on an angle to suit the garden path (this cant be moved as it follows the house).
    What I’m interested in is what gaps you left between the floor beams, wall uprights and the roof beams, you’ve listed the section sizes in the text (thanks), also having the insulation on the top of the roof sheeting, could this be placed inside the roof beams, (maximise the interior height, whilst minimising the overall height as much as possible)

  • Brian says:

    Great work man ship, I’m looking to build a 7x4m man cave could you tell me how timber I would need.

  • David says:

    I’m interested in building a mancave what do you recommend on a budget

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