Ronski finally starts his cinema room.


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Dec 14, 2006
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Sunny part of Kent
You can view the finished build here Ronski's cinema room finally finished (well are they ever finished??)

A bit of background history.

We bought this house because it was on a corner plot and looked ripe for extending to make a nice sized family home. I actually designed the extension, pushed it through planning, even took the planning officer around the estate when they tried to make me change my plans (it would of ruined it), in the end the council approved it as designed because other properties set a precedent. So we now have a nice sized 5 bedroom family home, I wouldn't say it's huge, especially going by some I've seen on here, neither is it high tech. The house is fully networked with Cat 5e, and networked Heatmiser thermostats. I have a server, various media centre PCs and a multiswitch in the loft sending freesat and and freeview around the house.


The server room.


I had a builder build the shell to weather tight (that was an absolute nightmare, with problem after problem), then I've done virtually everything else since then, including structural work the builders were not interested in, so it's taken a lot of weekends and a very patient wife (and daughters) to get where we are now. The extension was stated around 10 years ago, and I have finally got to the last room, which has been my workshop until now, and is going to be our home cinema/family room.

The cinema room.

Currently it is a bare brick room, the walls are thermalites, and the floor is a concrete slab, which extends under a block wall and the cloak room and utility room. The slab is about 130mm below finished height, but the concrete is not level, the opposite corner is 56mm higher! So the floor is very uneven, there is also 100mm polystyrene around 3 sides of the room, so the concrete is 100mm in from the walls. There is a pair of French doors in one wall, and a large window in the front wall. Dimensions are approximately 4.5 by 4 meters. Current height from finished floor level to the bottom of the floor joists above is 2335mm, so I can't afford to lose too much height. The room mainly sits on it's own with three external walls, the fourth wall has the utility room, cloak room and hallway, the kitchen slightly over laps on the rear wall. Above the cinema room is our bedroom, this has 3 layers of SBM5 sound proofing mat, Cloud 9 Cumulus underlay and a nice thick carpet. All gaps around the floor perimeter were sealed with soundproofing mastic upstairs, but I still need to do downstairs before the ceiling goes up.

I'm the only man in the house, I have two daughters and what seems to be a typical wife (would be happy with a 32" TV in mono!) so I need to keep noise to a minimum. With this in mind I'd like to minimize flanking sound as well. So will be building stud walls, much like a room within a room.

Cinema wise I plan on having a ceiling mounted projector, electric screen which comes down in front of the window, possibly about 110" but that's not yet decided. I'll have a lighting pelmet around the perimeter, to include LED lights and light strips - been getting ideas on here lately, but have very little knowledge of the tech involved. Also not yet decided on 5.1, 5.2, 7.1 or 7.2 sound system yet. So would welcome suggestion there for screen size, projector (possibly Sony HW40 as it's very quiet) and sound system. But that's all decisions to make later in the build. The amplifier and media PC will be in the cloakroom next door - which is my server room. Seating will be a corner sofa with electric reclining seats, seen a very nice one that gets the approval from SWMBO but it's looking a very tight fit.


This is what I've come up with after much research, and is my current build plan, I warn you now this will not be a quick build, it'll be nice to have it done by Christmas, but I'm not sure which one it will be. One advantage of a long build is it spreads the cost out, remember it's been 10 years so far.


I'm going to build a floating floor which is sat on 10mm thick rubber anti vibration pads, not sure how well these will work or whether they will just compress too much (by my calculations the finished room without furnishing, carpets, ceiling etc. should weigh about 1877kg). The floating floor subframe will be made from 89 x 38mm timber, but this will be laid flat and sat on plenty of pads to spread the load, then boarded with one layer of 25mm ply. The voids will be filled with fibre glass loft insulation. I will also use some of the rubber pads around the perimeter as spacers to give 10mm clearance from the blockwork walls. I've allowed 20mm for carpet and underlay, so this should give me the correct floor height to match the wooden flooring in the hallway once the underlay and carpet are down. This sub floor is the bit I'm really not looking forward to, if the concrete was level it would be easy, but as it is each pad needs spacing differently to end up with a flat floor.

This picture shows the subfloor construction.



For the ceiling I have found this Genie clip system, which uses 100mm 60kg/m3 density insulation between the existing joists, then the Genie clips and furring channel and then one layer of 12.5mm acoustic plasterboard, and one layer of plank 19mm plasterboard. The gap between the plasterboard and thermalite wall will be sealed with acoustic mastic. I'll use green glue between the two layers of plaster board. No lights are installed in the ceiling, and there shouldn't be any need for wiring through the ceiling either, that will go in the pelmet.


The walls will be 50mm metal stud work walls, fixed to both the floor and the ceiling furring channels, 10mm clear of existing block work. I'll use 50mm rock wall insulation to fill the void. One layer of 12mm plywood and two layers of 19mm plasterboard with green glue between all three. Total wall thickness about 104mm, so a loss of about 220mm room width. One complication with the rear wall is there's a step in the brickwork where the builders started building it in the wrong place, I'm hoping this doesn't push the stud wall out to far.

I've not yet finished drawing the stud work for the walls yet, but here's where I'm at.



I've not done much research on doors, but I want to keep the existing door as it matches all the other downstairs doors. Problem is it's a cheap pine glass panelled door. What I'm thinking of doing is getting a double glazed sealed unit made (just the glass bit) and a wood frame and fixing this to the inside of the existing door, and of course fitting some seals around the door, possibly with an automatic closer on the bottom to close the gap when shut.

Anyway thats enough off my ramblings, and the wife is calling, so I'd better go. When I get chance I'll add some various pictures of the room as it is, and also pictures of other rooms that I've done. As the build progresses I'll add pictures and info.
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Good luck! You've got you're work cut out but at least you have a solid well researched plan. I'll be watching with interest.
A little update on progress and some pictures of the existing room, and my previous work.

I finally managed to get a friend of my brothers to come round last night, he's been working for a home cinema installation firm for around 15 to 20 years, the kind of jobs he gets involved with is building and designing cinema's and complete home automation systems for the super rich all the way up to billionaires where money is no object. It's a very high end firm, in a totally different league to anything on here. He's a mind of information, but unfortunately for me he's rather hard to get hold of, jetting all over the world a lot of the time.

So I ran my plan past him, and he was in agreement with it, although they would usually install separate joists for the ceiling, but that isn't possible in my case as I have noggins between the existing joists and I can't afford to lose that amount of room height. He also said that given the room mostly had external walls it was a bit OTT, but should work well. He said that my room being square could well be a problem, something to do with standing waves. Another thing he said was you'd sometimes make one wall, normally the screen wall less sound proofed, which would make that end of the room more live. This is achieved in my room by the window being behind the screen.

He would recommend that a 5.1 system would be adequate for my room size, and also I simply don't have the depth behind my seating position for a 7.1 system. Regarding speaker placement he pointed me in the direction of this Dolby guide showing how various speakers should be positioned. He also suggested purchasing the screen last, as I could then judge what size suited me best projecting on to a sheet.

He said to make sure I could change the HDMI cables easily, as 8K HDMI standard is now well into development, although a good few years away yet as they have to flog 4k to death first ;-)

Here's some of my previous work.

I trial fitted the kitchen units, so I could build the plasterboard wall to suit the units.


And this is the end result, the only jobs I got people in for was plastering, fitting the granite worktops, tiling the wall and connecting up the gas to the hob. Note the date above, the picture below was 2 years 7 months later.


Our en-suite went from this.


To this, I did get my brother to help with tiling the wall behind the units as that was very uneven.


And another view.


The cinema room as it is.

This is looking from the corner with the door in, so towards the rear wall.


This view is looking from right hand corner in the above picture.


and from the other corner looking towards the door.


and from the remaining corner.


I didn't get that much done this weekend, but I did manage to get out to Wickes and buy 24 lengths (all straight!) of 38 x 89 x 2400 stud work timber which will be used for the floor subframe, I got bulk discount and an extra 10% discount.

I also altered the pipe work for the plumbing so that it's in copper and not plastic. It was like this.


It's now like this.


It was rather difficult soldering the pipes without burning anything, but I succeeded.

Just in case you are wondering what all the valves are for, they are the zone control valves that work along with the Heatmiser thermostats, there are another six in the bottom of the airing cupboard upstairs.

The pipes emerging the other side of the wall.


I'm currently waiting on a biscuit jointer to be delivered, and also my 10mm anti vibration mating.
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I think I'm all set for tomorrow, I have a stack of wood.


I have my anti-vibration rubber and my new toy (for any children viewing, please note it's note really a toy).


And I've progressed the Sketchup model.

Annimated Plan.gif

Got a little bit more plumbing to do first thing, then I'm going to start laying the floor battens.
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Got some work done today, extended my central heating pipes so they are above the floor level. I'm planning on having a couple of Quinn Adagio 35 vertical radiators, one either side of the screen.


And I also got the first two floor timbers down, although I've not fixed them together yet.

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Are you biscuit jointing all the joints in the floor? Or is that for later in the project? I would have thought that is really the long way round but I guess with timber that thin you haven't got many other options.
Yes I'm glueing and biscuit jointing them, couldn't really think what else to do. It just really to tie it together before the plywood goes on, as the ply wood will make it all so much stronger once that's screwed down. I've never used a biscuit jointer before, but apparently it's pretty quick.

Once I've got all the floor pads cemented in (and thus know clearances under the battens) I'm going to run trunking for speaker cables and the bass speaker, these will feed back into the room next door where the two copper pipes go.

If anybody spots anything I've missed or not done correctly, or has suggestions please shout.
Here's the weekends progress, my knee's are going to ache tomorrow.




I am wondering if there is anything to be gained by biscuit jointing all the joins, or to just rely on the plywood to hold it all together.
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I am wondering if there is anything to be gained by biscuit jointing all the joins said:
I think you have hit that point in the project where you have experienced just how slow progress is when you do things properly and to a high standard!! It would be easier to not biscuit joint the rest but imagine the satisfaction of completing it. Also, and I'm not saying this would happen if you didn't continue with the joints, but if you step on it and it creaks you will always think "what if".

Cracking work so far. Stick with it I've been there.
Wow using the quote option on the iphone is tricky after a few beers!
Thanks for the kind comments and encouragement pingpong. I haven't jointed any joins yet, they are all laid loose at the moment as I need to run my conduit for the speakers and whatever else needs to go under the floor. You can't see it in any of the pictures but I punched a hole through the wall near the pipes, all conduits will come through there, and I need to take the first batten (calling them joists just seems wrong as they are not big enough) out to be able to feed the conduit's through and then cement it up.

I expect I will joint it all, as you say don't wish to risk any creaks.
Is your floor not going to sag after a while if you lay the floor that way? I wouldn't biscuit joint either stagger the noggins and glue and screw a lot quicker as you said the ply will help keep it all straight.
I don't think it will sag, it's supported in over 100 locations on the pads, the whole room without furnishings or ceiling (the ceiling hangs from joists above) will weigh about 2000kg, meaning each pad only takes 20Kg, although most of the weight will be closer to the walls, so those pads will be loaded higher, but there are 15 pads under each wall. The walls will weigh a total of around 1500kg, so an average of 375kg spread along their length.

We actually did structural calculations to make sure the polystyrene under the floor slab (slab weighs about 3500kg) could take the weight of the room/walls, and it is well under, and that's not allowing for the spreading affect the concrete slab has which further reduces point loading.

My only concern was where the timbers extend out past the edge of the slab, as the builder put 100mm polystyrene upstand around the edge of the slab. But if we take one wall of 375kg, divide by the number of timber supports which is 9, we get 41kg. But that 41kg load is spread along 438mm of wall, which then spreads out through the ply floor, which is 25mm WBP, so pretty strong stuff. I expect even if you put 41kg directly on the end of the timber it wouldn't bend, there's about 90mm sticking out past the pad. There may be some deflection, but very minor.

If I staggered the noggins they wouldn't be under the joints in the ply, I would also need to either use 140mm screws or counter bore them all. So it's a bit catch 22, trying to squeeze so much into a small space has it's complications.

Hopefully my brother and I have got our maths correct, as well as our assumptions correct.
Just reading through some of the comments since my last wasn't meant to be taken as 'don't biscuit joint'.

Looking at the pictures Ronski, would (and it is a question ;)) it be beneficial to move that length of timber parallel to the door away from the wall? Or at least doubling the width? I'm just thinking that as it looks now, when you fix the plasterboard to the walls, the plasterboard will be over the top of the fixings in the if you ever need to lift the floor in future to run/replace cables etc, you'll need to cut the ply and or the walls. If you put the fixings slightly out from the wall, you can take them out, lift the floor run the cables and replace without any problems...

Of course if you're glueing the floor down completely and have no intention to ever lift it then it doesn't matter.
Hi Geps, the plasterboard isn't being fixed to the wall. A metal stud wall is being built off of the floor for maximum soundproofing, this means it won't be possible to lift the floor, except the middle sheets. The plywood also forms part of the structural integrity of the floor platform.

I've created a thread in the cables forum which will hopefully give me the information to cover most known eventualities, and also describes my current thinking on how to wire things up so cables can be changed if required.

I will be biscuit jointing the floor beams, now I've bought the tool I need to have a play, although I'm sure it will be useful for other things, I can think of loads of jobs I've done where it would of made things easier or better.
Just a quick update before I start my days work, this week I ordered the following.

From Wickes.
  1. Kemfast 2 resin 380ML cartridges Qty 6
  2. Kemfast 2 Pk 10 spare nozzles Qty 1
  3. Kemfast 2 Cartridge Gun
From Screwfix.
  1. 10m of Tower Corrugated Conduit Black 20mm x 10m (QF 50443) Qty 3
  2. Spring Steel Fish Tape (QF 67849)
  3. Spax Flooring Screw Zinc & Yellow Passivated 4.5 X 60mm Pack of 300 (QF 88716)
  4. JSP Anti-Mist Pro Safety Goggles (QF 11964)

From Ebay seller ukcablemanagement
  1. 32mm flexible conduit contractor pack 10 Mtr inc. 10 glands & nuts (M32) Qty 1
  2. 25mm flexible conduit contractor pack 10 Mtr inc. 10 glands & nuts (M25) Qty 1
The stuff from Wickes and Screwfix has arrived :)


Had a couple of problems with Wickes though, instead of sending a pack of 10 nozzles they sent 1 nozzle! So I phoned up, took about ten minutes but they agreed to send another pack. Yesterday another single nozzle turned up via DPD! So on the phone again, spoke to someone, then put on hold, then got cut off. So phoned again, this time got someone quite helpful, put a load of notes on the system and requested 8 more nozzles to be sent out. So whats going to arrive on Monday, 1 nozzle, 8 nozzles, 10 nozzles or 8 packs of 10? You do actually get two nozzles with each cartridge, so I should have enough either way.

I'm really pleased with the cartridge gun, this is actually substantially built, not like the usual flimsy things you get. Anyway the resin is for levelling the pads which are going to be that bit too thin for cement, and for repairing some cracks in the thermalite - I normally just resin bond some studding across the cracks to tie it back together.

The fish tape seems to work quite well, I tested it this morning, it works fine in the conduit I just need to make sure there is no tight bends halfway through the conduit route. I will end up with one tight bend where it comes up through the floor, so will need to feed the fish tape in from that end, it then feeds through ok. If I do have any problems then there is the old trick of cotton wool and cotton, sucked through with the hoover, then pull some string through with the cotton.

The flooring screws are for the 25mm ply, and the goggles, well I needed a new pair and it made the order up just enough to get free carriage :)
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New goggles are so nice, I can actually see what I'm cutting now :)

Here's yesterdays progress, had to finish early yesterday as I had to get the BBQ out and have a party :thumbsup:

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It's been a very dusty afternoon, I've ground out the concrete where the pads needed to go in the far corner, in fact I wore out my diamond cutting disc :(

The wife wasn't happy either, even though I had the French doors wide open, and the other door closed the dust still went through the house, even made it to the kitchen!


The following two pictures will give you an idea of just how uneven the concrete is, the first picture is where the door is, then the second is where I've had to grind out the concrete. I know it wouldn't normally matter if the floor was screeded, but it would have required 4.5" of screed in the deepest part :eek:



And here it is with the corner pads in place.

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In answer to the question as to how many nozzles will arrive from Wickes, they sent yet another single nozzle, so I phoned and cancelled the order and requested a refund, which they've done. In the end I didn't need the additional nozzles anyway.

Yesterday I completed cutting the wood for the floor and installed all the pads, there was a bit more concrete to cut out, which is not the best thing to be doing on a very hot day. The sun was so bright in the morning I had to hang an old blanket across the French doors so I could see the laser level.



I had to purchase an extra length of wood in the week, so a total of 25 2.4 meter lengths, and this is all I had left over, so did very well on the wastage side of things.


Here's the finished frame, although not yet fixed together.




I've started running in my various conduits, the first one will probably never be used unless the price of FTTPod drops substantially in the future. It will allow the fibre or other communication cable to go straight through to the server room. Edited 19/08/2020 to add we got Virgin in April 2018 and FTTP is on it's way :clap:


So far I've run in two 32mm conduits which go to a central position under the window, as we may have a TV here in the future. I'm using the two existing 25mm conduits for the subwoofer to allow for two different positions. I've also run in 4 x 20mm conduit for the rear speakers, as I'm putting in enough to have 7.1. Today I need to run in 2 more 20mm conduits for the front speakers. All 20mm speaker conduits will come up through the floor for floor standers or stands.


Today I plan on getting in the last two conduits and then cement up the hole in the wall, not that there is much hole left! Then to get as much of the floor frame joined together. If things progress well I'll get the plywood delivered in the week for fitting next weekend.
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Looking good, nice to see someone doing a full planning session before starting.

Just wish i had seen this before you put the conduits in as i would have suggested putting a length of string / Single cable into each conduit to use as a draw wire, would negate the need for the the draw tape then.
All the conduit wants to do is coil itself up, so it's probably easier to thread something through afterwards once it's fixed in place and cut to finished length. If I can't get the draw tape through I'll tie some cotton wool on the end of some cotton and suck that through with the hoover, then pull the string through. I'll post some pictures soon to update on today's progress.
Made good progress today, but boy do I ache, back to work tomorrow for a rest.

The biscuit jointer works really well, probably the hardest part is squeezing the glue out the bottle.


First couple of row jointed and strapped together by about 13:30


And this is where I was at by 18:15 You need to be a bit careful with the straps or it will start to lift the timbers, you just need enough tension to hold it together, as I don't have any sash clamps that are long enough.



Just two rows left to do. In the end I cut a chunk out of the timber where the conduit goes through the wall, as there wasn't enough space under the timber. The subframe feels really solid now, can't wait to get the floor on top.


The conduits will all be tidied up before the floor goes down next weekend.
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I received my 7 sheets of hardwood WBP 25mm plywood yesterday, and just had to try one to see what it looked and felt like.


The aim for this weekend is to get the floor finished, so I'd best get to bed. :zonked::zonked::zonked:
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Made good progress today. I replaced the damaged damp proof membrane.



I've got all the subframe glued together, it's now nice and rigid.



I've put pipe insulation on the heating pipes mainly to protect them from chaffing by the plastic conduit, it was left over from before so might as well insulate all the pipes. I also had a bag of plasterboard adhesive left over from previous work, so I've used that to fill the hole where the conduit goes through the wall, and also to fix the pipes in place, which makes them more rigid. This should help when it comes to feeding things through.


And the other side, where I'll probably run some separate trunking up the wall, so the various AV cables are not too near the heating control cables.


And what look like large cow pats on my conduits.



Tomorrow I'm aiming to get the plywood floor down, which will mean I need to get the stuff for the ceiling ordered.
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