Integral Garage Conversion


Standard Member
Now seems as good a time as ever to start a thread about my Current project. I have spent many years following threads started by others carrying out conversions of every scale in pursuit of a dedicated home cinema room. These threads have provided a tremendous amount of inspiration when planning my own, plans which have evolved each year as my own project has failed to come to fruition.

In writing this thread I hope that I too can help others down the line whist taking on their own project, I will make all costing and plans available for all to that end.


In 2009 I began giving serious consideration to converting an integral garage into a media room. A great deal of time went into measuring and mocking up a workable solution using Google Sketchup, unfortunately however, disaster struck. An unforeseen financial black hole appeared beneath my partner and I. As we struggled to balance the books it became obvious that the conversion would not be happening that summer, previously thought to have been completed for commencement of the 2009-2010 NFL Football Season. Left over materials from previous projects would remain.



All thoughts about the conversion were put on hold pending a change in fortunes but by the time the summer of 2010 rolled around, together with a stronger financial outlook, all thoughts were on taking a well-deserved holiday and so once more, the conversion was dismissed.

This summer, our savings are ear-marked for a three week break in America, taking in New York, Las Vegas, Los Angeles, and San Diego. This blow out is no ordinary holiday and will see my partner and I celebrate my 30th Birthday watching my NFL Team in their home stadium whilst also enjoying our honeymoon following our Vegas wedding.

With so much going on I was speechless when she who must be obeyed gave the nod to go ahead with the much maligned garage project. A budget of £1500 and four weeks off work were earmarked for the work which would all be carried out with my own fair hands alone.

I am a complete DIY novice but I have always enjoyed working with wood and have a knack for picking things up quickly. I armed myself with the Collins book and spent many hours thinking the process through, reading up on the appropriate building codes and requirements.


From the outset the project was intended to leave the existing garage door intact with access provided by a new opening created in the hallway. Unfortunately, due to the existing floor plan, this leaves no space behind the door for storage and so in effect, the garage door will be false and sealed in a closed position. The reasons for leaving the door intact are two-fold, the first being that I am seeking total darkness to benefit my projector setup, the second, and critical – cost.

Consideration was given to carrying out the work without notifying the local building office but ultimately the decision was made to do things by the book, for better or worse! The original plans were revisited, revised, and in some cases, redone.








These drawings were annotated based on the construction methods and building regulations I had started to become familiar with in order to confirm with the local BCO that I was on the right track. It has to be said, I have read some real horror stories written by people in my position when dealing with the building office but in my case, the guy has been very helpful and accommodating from the outset. As a DIY enthusiast his knowledge has been worth the £160 fee in the planning stages alone. In went the new doorway, fitted by a contractor at a cost of £270, a bargain and significantly less than originally budgeted. In a load bearing wall, this was one area that I was not prepared to turn my hand.

After a minor flood (curse plastic piping!) the door was complete and ready to be painted several days later when the plaster had completely dried.




A building notice was submitted and acknowledged by the BCO who pointed out that no planning permission would be required because no external changes were being made. Unfortunately, having received that verbal advice, I went on ahead and made the first orders of materials at a cost of around £1100. On the day those materials arrived, the floor went down within a couple of hours.




This proved just long enough to receive the days post from Royal Mail, a letter from the Planning Office stating that I did require planning permission after all. This was a dark time. Fortunately it was a very bright and sunny day and so I lay flat on the driveway staring at the clouds terrified that the financial black hole would soon be opening up again.

It transpires that as part of the original approval given to the builder or my home, the right to convert the integral garage was removed. As this is a four bedroom detached house, it requires space (or potential space) for three vehicles. A double driveway takes care of the first two, the third required the submission of plans to prove that space exists within the boundary for the addition of a third space should it be required.




These plans are yet to be submitted but it does appear that I can more than accommodate the required hypothetical third space, and since no external changes are to be made, planning approval *should* be given. Fingers firmly crossed.

And that brings us up to date. I find myself at a loose end today awaiting delivery of Breeze Blocks, Bricks, and stud frame timbers on Thursday. The time has been spent looking at how to extend the existing ground floor ring main to accommodate the requirements in the new room. A double socket exists on the rear wall but the temptation to extend the ring while I can, taking care of all electrical needs in a ‘first fix’ environment prior to boarding might be too much to resist. Indeed it may be foolish. My understanding is that adding sockets or fused switch connections is not notifiable work providing that they are outside of special areas (bathrooms/kitchens/outdoors). I would need to have the work checked by an electrician and certified should I decide to move house however.

I am happy to answer any questions regarding my experience with Building Control and pass on his guidance in respect of required insulation etc. Feel free to ask and thanks for reading.


Well-known Member
Looks like a good start and good luck with the planning.

One question I have, if the walls are cavity (and I'm assuming insulated?) why do you need to then insulate again with the 50mm boards inside? Typically these are only for solid walls......


Standard Member
To be honest Geps, I am not entirely sure. Those drawings are a little dated from the spec I ended up using on advice from the BCO. The boards on that external wall are now 40mm Kingspan. Originally he wanted the floor to be composed of 1200Gauge DPM, 75mm Kingspan insulation, and 18mm T&G flooring. Unfortunately, due to the level of the existing DPC the new opening in the hall opened at about 50mm from the existing slab in the garage which would have meant a step up into the room.

The BCO was quite understanding and agreed to drop the 75mm down to 40mm with 12mm T&G to finish. To meet the overall U-Value requirements he has specced an over engineered approach to the external wall and to the blocked up garage door.

If you thought 50mm on the wall was bad, he wants 215mm thick thermalite blocks with 100mm Kingspan over, finished with a studwork frame and 12.5mm acoustic plasterboard to stand between the room and the garage door. Sure makes the simple stud partition approach sound like a breeze doesnt it!


Well-known Member
Definitely good luck on the planning.

One word of advice which was my sticking point for a garage conversion - we were required to leave a second means of escape in the room since our only exit was via an internal door. It was a legal thing, in order for the room to be signed off and regulated we had to make sure there was a window in.

This is your setup too, you have an internal escape route but no external escape. I would check not only with planning approval but with building regulations too.


Standard Member
Hi Wootball. My understanding of the building regs prior to submitting the notice was that a conversion of such a garage could go ahead without adding an escape window providing:
1. Access/Escape from the room is provided directly to and from the main hallway within x of the main entrance door
2. A hard wired, battery backed up, smoke alarm is situated within x of the new doorway

I cant recall the exact distances but mine falls within the permitted limits. The BCO has visited three times so far and understands that there will be no window. Not having a window brings its own challenges though in regards to ventilation. Background ventilation through trickle vents above windows is all too easily overlooked. Without adding a window it is a requirement to provide mechanical ventilation. I am using a manrose bathroom extractor fan which turns over 85m3 of air an hour to meet that criteria.

The garage has a double socket at the rear which is on the ring main. A document sent by the BCO explains that installing new sockets or fused connection switches is not notifiable work so long as it is done outside of a bathroom or kitchen. I plan to break into the existing ring using a twin accessory back box and two single sockets. I can then continue the ring around the conversion starting at one of the newly fitted single sockets. I will provide new sockets and fused switches for my projector screen, equipment, and the ventilation fan before then closing the circuit back where we started at the second of the single sockets in the back box. This will re-estabish continuity of the ring circuit and will provide the best means of meeting the supply demands of a cinema room.

I am glad you raised those points though, from the outset the purpose of this thread is to document my experiences in trying to do the job within the building regs so that it might help others plan their own conversions.

Work carried on today included repainting the garage door to provide a stronger weather barrier. As the door will be screwed closed for many years I felt it important to improve the flaking paint surface to prevent rust forming. Once the door is closed and the wall built behind I am at the mercy of the door staying intact because it wont be possible to open it and carry out repairs without knocking down the new wall and interior finishing!

B&Q are due to deliver the last of the outstanding materials tomorrow, not least of which is the breeze blocks, mortar, and stud timber. The real work starts with the wall itself tomorrow evening. Total cost to date, £1700 apx.


Well-known Member

I have converted my garage 2 years ago. I went down the window route instead of leaving the garage door as i listen to as much music as watch films.

In your first post you show a vent out to where the boiler is and then a fan to the outside world. Will this be enough to take the heat away as your room will get hot from the projector and AV equipment.

If you have it as one room will the fan be noisy as they usually are?

Have you any plans for heating, i put in a radiator at the window end.

Enough questions from me.

Good luck and keep the pictures coming



Standard Member
Morning DrH.

To be completely honest, the ventilation regs confuse the hell out of me. The BCO is quite a laid back bloke and has been golden so far, im hoping he will have some good ideas for the ventilation requirements. As you point out, the room is going to be partitioned at the rear where the boiler is. That partition will house a metal shelving rack pretty much from floor to ceiling with AV equipment opposite the boiler. I am quite energy conscious and tend to have everything turned off except when in use so I dont anticipate heat build up being significant outside of the 2-3 hours max use once every few days / once a week. The only thing running constantly will be an old Dell PC which I have running FreeNAS. That server is currently in a cupboard surrounded by the Mrs clothes threatening to set the whole house on fire.

A change from the drawings above, the BCO wants the fan in the main room, not in the equipment cupboard for some reason. I am extending the electrical ring to include new sockets in the cupboard and fused switches for the screen and extractor. When in use for a movie, the extractor will not be turned on ;)

The way I have worked it out thus far is that the fan provides an air exchange rate of 85m3/h. The floor space comes to 28m3 in whole and around 22m3 for the room without the cupboard space. That allows for very very close to 4 changes an hour which I believe to be the regs requirement. It is far from an elegant solution but at £20, its considerably cheaper than putting a window in. For now.

In two questions you have highlighted the two biggest ball aches Ive faced. Well done!

Regarding the heating, you have kind of answered that yourself. I know from experience that the current bedroom/cinema gets hot from the projector but not unbearably so. The dimensions are the same size as the new room so time will tell how warm it gets. The new room will be infrequently used and so for the time being I am going to see how it goes without heating. As winter draws in I will probably pick up an electric heater and further down the line I can tap into one of two radiators on adjoining walls when the budget will allow. As you have / will see as the thread goes on, the insulation in the room is absolutely insane, its going to be a trial and error balancing act until I am happy with the heating arrangements all year round.

On with the photo update!

B&Q dropped off the blocks and materials for the new wall...


Unfortunately the quality controler was having an off day...

Credit where its due, an hour and half later the pallet was swapped and work commenced.
A layer of engineering brick to bring level to the existing Damp Proof Course which was then laid and wall starter ties fitted.


Onwards and upwards!



This one was taken whilst sat on the stairs aching like I have never ached before.

Building a wall has been ridiculously time consuming and painful work. I am not entirely happy with it because I have struggled to keep block placement close to 'a block and a half' so to speak. It is however very strong, sturdy, perfectly level, and plumb.

This morning, battle resumes and the wall will be conquered!
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Well-known Member

looks like hard work, i paid a builder to do all my brickwork etc. I just did the electrics and AV cabling.

I like the idea of all the kit going into a room behind.

My garage was integral to the house but built outside of it if that makes sense. What i have found in my room with regards to the heating is that it gets much colder than the rest of the house as the heat does not get into it very easily. I have a large radiator at the window end. When it is very cold the other end, the screen end that is, the screen end of the room remains cold. Thinking about it in your case with the boiler behind that should help quite a bit.

Will watch with interest.

Good luck with the blockwork



Standard Member
Sorry for the delay in posting an update and photos, I have been somewhat engrossed in getting the room finished before starting back at work on Monday.

I have no idea where July has gone, the project has been a blur of days and nights with only changing DJs on Radio 1 to give me an idea of the passing time!

I am not yet finished but have reached a 'clean' stage after a LOT of hard work, cut fingers, swearing, and many trips to Screwfix.

The wall was finished and insulated.



Then up went the frame and partition.



The biggest challenge by far was running the electrical wiring and drilling out the holes in each of the vertical studwork beams, corners being an absolute nightmare to tackle.

The BCO has been in a few times and confirmed he was happy for me to extend the ring from an existing socket at the back of the room. Adding sockets and lights to an existing circuit is non-notifiable work but the BCO had to double check that extending the ring could be considered 'adding a socket'. Thankfully, he came back to me the same day with confirmation that he would not require a Part P certificate in order to sign me off.

I spent alot of time reading up on wiring before starting and have been able to stick to Part P regs whilst documenting the runs and connections for certification in future (should the house be sold). The cables at the top of the frame as seen in the photos are electrical (2.5mm Twin and Earth) and sit within the NICEIC safe zones etc. Cables run outside of those safe zones are AV.

The boarding was relatively simple with only a few frame adjustments needed where joins fell slightly outside of the correct centres. Filling the gaps and 'making good' was also quite straightforward though terribly messy work. The amount of dust from the sanding was unreal and I must have inhaled tons of the stuff. I wont tell you about the gunk I have been expelling from my nose and throat.... If noone takes anything from this thread other than this one point I will be happy - wear a dust mask!

New wiring includes a socket for my computer monitor which will be situated on an extending wall bracket beside the sofa. A DVI cable has been run through to that point from the back room where the rest of the AV cabling exits the wall beside a row of vertical sockets for AV kit. A shelving system is yet to be installed to hold it all.

You get an idea of the layout from the rest of the pictures which I will leave you with for now. On with decorating!





The final picture shows the screen wall awaiting paint. The box in the top left is a fused switch ready to power the projector screen alongside the 12v trigger cable hanging free and longing to be plugged in. The box in the top right is just a junction box containing the join in wiring for the relocated light switch, regs forbids you from burying a join in wiring and I did not want to take the floor boards up in the room above to run a new length.

The boxes towards the bottom of the wall are speaker / sub outlets.

Thanks for the continued interest!


Well-known Member
Looking good
You have got a lot done in a small time


Active Member
This is a really nice project - a lot of attention to detail, and very impressed you've managed to do nearly all of it yourself!

Incidentally, are you having the main walls skimmed over before you paint?


Well-known Member
Me too!

Best decision you've made it taking pics from start to finish. I still can't believe it when I look back at mine.


Standard Member
I am so close to completion and I can almost hear the projector firing up! I have more pictures to post soon. I have just gone back to work but I have taken night shifts off this weekend to get it finished. We decided not to have the Walls skimmed and I don't regret the decision, I have used drywall filler in all of the joins and did quite a lot of sanding to make good. My partner has spent all week painting and I have been assembling the rear room shelving today as well as drilling and spray painting blank wall plates black for speaker cable outlets. The carpet arrived today an I have hung the projector too. Wiring the screen is going to be a total nightmare. I have a fused switch in place ready to power it but I have positioned the switch high on the wall directly behind where the screen will hang. I won't be able to fasten it in place and then wire it in and so it's going to literally be a balancing act between me and the mrs while I connect the cable to the load side of the switch. Absolute nightmare scenario.

I will post a full photo update after the weekend. The premiere is likely to be tomorrow (or Sunday night!
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Well-known Member
Good luck:smashin:

Any ideas on the film for your premiere



Standard Member
After four weeks and very close to £1900 the project is complete. The BCO just made his final visit and has gone off to sign the paperwork. Unfortunately I am still officially waiting for planning permission after having to re-submit two drawings. Fingers still crossed.

I made at least one monumental error though and none of you spotted it!

It turns out that my partner has been stealth documenting the same project and so before I post the finished room I will recap with a few of hers to give a second take on what we (I) have achieved ;)

It all started with the new door opening, the do or die moment when there really was no turning back really.


Then came the blockwork, a back breaking, finger ripping, nightmare of a task that was arguably my proudest moment. The Mrs has caught me in one of my camper stances in this one, god bless her.


Then came the studwork, insulation, and wiring stage.



Then came boarding, making good, and sealing



which took us up to painting and decorating.



Once we were dry, all that was left was to fit the carpet, spray the wall plates matt black, fit some shelves, put up some wall art, build the furniture, hang the projection equipment, wire up the AV kit, calibrate everything, and watch the premiere...


Standard Member
Here she is, the finished conversion.








Oh, the monumental error...

On the day that the paint had dried and everything else was taken care of I decided to fit the carpet. It was getting late and by the time I had finished it was two hours later. Proud as punch I decided that it was too late to start playing about with equipment but decided to treat myself to a sneak peak at the high gloss KEF sub in its place on the front screen wall floor.

It wasnt until I set it down on the carpet that I realised what I had done. In all of my electrical planning I had forgotten that the sub needs a socket. The nearest one is at the back of the room on the side wall beneath the Banksy Pulp Fiction decal.

I sat dejected for quite some time, angry at myself for making such a basic error. Then I picked myself up and ran a second sub cable to the second location under the skirting boards, fortunately I had left a good gap and the carpet tucked in over nicely. A blanking plate hides the original sub cable where it should have been.

Failing to plan is planning to fail!

Ill leave you with a picture of my poorly dog watching TV in the living room, last years project. Thanks for following my thread.

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Active Member
Love what you've done. Great work from start to finish and just shows how key it is to plan beforehand. Have enjoyed seeing this one progress from start to finish..thanks you!



Well-known Member
Great work and a lovely room for you to use - good job! Being honest I reaaaallly don't like the decals, they're a bit too obtrusive for me but that's just a difference in taste.


Standard Member
The jury is still out on those decals here too. They are situated behind the sofa so that they are completely out of eyeshot when watching anything though. It's a dark room for the projector and we found it difficult to come up with anything that would work on such dark Walls. Money permitting there are lots of little things I'd like to dress up a little bit with finishing touches but the money is all for the wedding trip until next year now. The mrs took my going over budget reasonably well. We had hoped for £1500, at one stage looked like doing it for £1300, and ended up spending £1900, including an emergency sale of my iPad on eBay to pay for paint, wallpaper, rug, cushions, and the coffee table ;)

I don't think the pics I've posted really do it much justice. I'm going to have another shot with a better camera later. Thanks for the feedback guys.


Standard Member
Sightly better pictures, its proven really difficult because of the low light and poor cameras. I have used a panorama app on the iphone to give a wider field of view but as a result some of the lines appear sightly curved, rest assured the doorway and projector are straight in real life!



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