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Just found your topic, Rob, and will follow with interest.

 

I, too, am needing to create a suitable environment for my layout (though unlike you, I did not do so before starting work on the layout!).

 

My next major job in that regard, and an essential one before the winter, is to add insulation between the rafters. 

 

Of course, in my case I am dealing with an out-building.  In your case, you are dealing with creating accommodation and are subject to Building Control Regulations, so insulation requirements may be very different. I don't plan to do anything that would trigger the application of any regulations, so, men with clip-boards, look away now ...

 

Rafters are generally deep enough to allow a 50mm air-gap if the insulation is mounted between the rafters flush with the inner edge.  B&Q (other ways of wasting a weekend are available) make expanded polystyrene rafter panels that have pre-formed grooves, which allow them to bend and slot in between the rafters.  

 

To ensure the air-gap, one would need to screw battens on to the rafters for the insulation panels to butt against, but no other fixing seems to be required.

 

Here all is explained: http://www.diy.com/help-ideas/how-to-insulate-your-loft/CC_npcart_400221.art

 

My workshop has a couple of small vents under the ridge tiles. 

 

I do not know how effective this material is, and buying it in pre-grooved form is not cheap.  If I simply cut insulation material to fit, however, I can expect some gaps in places, and would need wood for battens to hold the sheets in place. There would also be much more mess. 

 

So, I thought this might be of some interest, and, of course, if anyone has any other/better suggestions .....  

 

P.S. Having checked the B&Q site, I can no longer find this rafter insulation!

 

Discontinued, just like that grooved bendable MDF I was going to use for my back-scene that they stopped doing?!?

 

No, it's still there, just don't search using the product name "Rafter Insulation", or the location of installation "loft insulation", and you'll find it(!): http://www.diy.com/departments/bq-insulation-board-610mm-402mm-60mm/182547_BQ.prd

 

"... if anyone has any other/better suggestions ..... "

 

That polystyrene insulation is expensive.  The website doesn't say how large the packs are but the pictures show four sheets, so you would need three packs to make the equivalent of a standard 2.4 x 1.2m board making it £33.66.  For that price you could buy PIR insulation (brands include Celotex, Kingspan etc.) which provides a significantly higher insulation value.  So you could either get better insulation or use thinner board.  Even at B&Q prices you could buy 50mm PIR for £36.  (Available elsewhere for around 40% less though you have to factor in delivery if ordering smaller quantities.)

 

Amongst the DIY chains Wickes might be cheaper or their associated company Travis Perkins.  I buy some things from B&Q but most of the time it is cheaper elsewhere.

 

For fixing, you are correct in saying that battens are required but these need only be nailed in place and serve no other purpose than to prevent the insulation panels being pushed too far in.  My solution is to tape a marker pen to a suitable spacer and mark a line 50mm from the underside of the felt then nail battens (treated timber) to this line.  The insulation is then cut so that it is a firm push fit between the rafters and holds itself in place.  Because I am complying with Building Regulations I need to achieve a certain level of insulation, so I will then be fitting a further layer of insulation across the face of the rafters.  Don't underestimate the importance of not leaving gaps and, in the case of Building Regs., the requirement to seal joints with aluminium tape.  (Incidentally, if the roof has a modern breathable membrane rather than traditional felt the air gap can be as little as 30mm.)

 

The additional layer of insulation across the face of the rafters also minimises thermal bridging.  In the case of rafters just think of this as heat being conducted from the warm inner face of a rafter to the cold outer face.

 

A vapour barrier is also required.  In the case of PIR insulation this is built-in via the foil facing on both sides (and maintained by the aluminium tape).  If using "wool" type insulation a polyethylene membrane is usually fixed to the inner face.  I'm not sure about expanded polystyrene.

 

 

"My workshop has a couple of small vents under the ridge tiles."

 

You've probably thought about this but the vents will need to connect with the gap at the back of the insulation and not connect to the room.  You may require some background ventilation though for the room itself - the kind of thing provided by trickle vents above windows.

 

 

BTW - B&Q still list "bendy MDF" on their website.

 

 

Right then.  Anyone still awake?  :dontknow:

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Mesh

 

Fire regulations require 100mm of loft insulation supported by strong 20 gauge, 25mm wire mesh.  The existing loft insulation is in reasonable condition so this can be reused and just topped up where required.  The easiest way to install the mesh is to staple it to the ceiling rafters before the new floor joists restrict access.

 

For my birthday Mrs Teaky bought me an electric stapler which makes the job so much easier.  (Now there’s a difference between the sexes.  Just try buying your wife a new household appliance instead of a pair of shoes or a frock!)

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I presume your making a tray with the mesh between the joists, have they asked for a layer of plasterboard as well?

I have to do this but it's between flats/shop

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I presume your making a tray with the mesh between the joists, have they asked for a layer of plasterboard as well?

I have to do this but it's between flats/shop

I haven't been given any specific instructions beyond a brief discussion with the BCO several months ago where I agreed the area to be covered (the complete new room but no need to do the eaves area).

 

The existing ceiling is 12.5mm plasterboard with a textured plaster coating.  The regulations just specify a 40mm gap between the plasterboard and the mesh so I've simply stapled the mesh across the ceiling joists and not worried too much about a little sagging.  The ceiling joists are 80mm deep so the 40mm gap is easily achieved/exceeded.  The new floor joists will sit 20mm or so above the ceiling joists with insulation between them.

 

Are your shop ceilings plasterboard or lath and plaster?  Perhaps it's just an extra requirement for commercial properties?

Edited by teaky

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Boy is this a boring job!

 

post-9672-0-37674200-1505930806_thumb.jpg

 

Believe me, the photo is more exciting than the task!

 

I have some mesh left over so future model scenery is likely to mesh and papier mâché.  (Unless anyone wants to make me an offer for the mesh?)

 

Mind you, there's one side benefit of all this work in an unventilated loft in summer: I'm now several kilogrammes lighter than I was when I started.

 

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Hi Rob,

 

I too have just found your thread and I wish you all the very best with the conversation.

 

I won't go into a lengthy or technical diatribe but i'm pleased to hear that you are able to employ someone to carry out the " heavy work" to comply with current requirements. It's a MUST in my opinion and I believe it to be the correct way for such work, whether it be for "puffer trains " to live in or family members.

The prime objective being safety for all who occupy the house and ultimately a place to be enjoyed for whatever use it is put to.

As I've said several times before elsewhere, as a retired Building Control Officer and fellow modeller get it correct and compliant from the off it will hopefully pay dividends in the long run.

 

I wish you well and look forward to your progress.

 

Grahame

Edited by bgman

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Hi Rob,

 

I too have just found your thread and I wish you all the very best with the conversation.

 

I won't go into a lengthy or technical diatribe but i'm pleased to hear that you are able to employ someone to carry out the " heavy work" to comply with current requirements. It's a MUST in my opinion and I believe it to be the correct way for such work, whether it be for "puffer trains " to live in or family members.

The prime objective being safety for all who occupy the house and ultimately a place to be enjoyed for whatever use it is put to.

As I've said several times before elsewhere, as a retired Building Control Officer and fellow modeller get it correct and compliant from the off it will hopefully pay dividends in the long run.

 

I wish you well and look forward to you're progress.

 

Grahame

Hi Grahame.  Nice to have you on board.  I know from previous threads where lofts and other railway rooms have been discussed that we're on the same page.  Thanks for your encouraging words.

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Mesh

 

Fire regulations require 100mm of loft insulation supported by strong 20 gauge, 25mm wire mesh.  The existing loft insulation is in reasonable condition so this can be reused and just topped up where required.  The easiest way to install the mesh is to staple it to the ceiling rafters before the new floor joists restrict access.

 

For my birthday Mrs Teaky bought me an electric stapler which makes the job so much easier.  (Now there’s a difference between the sexes.  Just try buying your wife a new household appliance instead of a pair of shoes or a frock!)

I once bought my ex-wife a steam wallpaper stripper for her birthday.

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I once bought my ex-wife a steam wallpaper stripper for her birthday.

Ummm - a steamy stripper..........

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Hi rob

My ceiling is a real headscratcher, I have s first floor area which I'm turning into a bedsit. I have a flying freehold which states I own the joists down to the ceiling but not the ceiling which belongs to below. The existing is softboard with no insulation. So anything is better.

I have to put new joists in between existing as there isn't headroom to place above.

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I once bought my ex-wife a steam wallpaper stripper for her birthday.

Did she become "ex" as a result?

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Hi rob

My ceiling is a real headscratcher, I have s first floor area which I'm turning into a bedsit. I have a flying freehold which states I own the joists down to the ceiling but not the ceiling which belongs to below. The existing is softboard with no insulation. So anything is better.

I have to put new joists in between existing as there isn't headroom to place above.

Complicated.  As I'm sure you know, the aim is to achieve a 30 minute fire resistance so it sounds like plasterboard is the simplest option.  I'm struggling to picture where the plasterboard goes though unless you're being given access to the property below to install it on the underside of the softboard ceiling?

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I'm going to put it in between the existing joists, there's not much else that can be done.

 

As you're joists are on top of the existing are you losing much headroom ? In the past weve suspended the new in between the existing

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I'm going to put it in between the existing joists, there's not much else that can be done.

 

As you're joists are on top of the existing are you losing much headroom ? In the past weve suspended the new in between the existing

Blimey, that's a faff.  You have my sympathy.

 

 

Unless my calculations are out the headroom should still be OK.  The existing ceiling joists are 80mm deep, so after subtracting a minimum of 40mm for the air gap below the mesh plus a few millimetres to maintain separation between the ceiling joists and new floor joists there didn't seem to be much gain.  I suppose I could have waited until the floor joists were in but there are a few other minor obstacles (pipe, cables, TV booster) to find a way around and in the end it didn't seem worth the effort.  There's an additional saving in installation time too which, I think, has kept the cost down.

 

I'm fairly tall so I'm already resigned to only being able to stand up in the centre of the room (unless I open a window :jester: ).  The most significant height gain came from getting the Structural Engineer to re-do the calculations so that there were two steel beams at the sides rather than two smaller side beams plus one at the ridge.  I wouldn't have been able to stand up anywhere if I'd gone with the first version.  At the same time I gained an additional 20mm from differently dimensioned floor joists.

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Lofts are always a trade off with headroom, to keep the floor joists to a minimum you could look at JJI joists, although they may only offer 10-20mm max

The only way to achieve more headroom is a dormer window, but they add significantly to the cost.

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Lofts are always a trade off with headroom, to keep the floor joists to a minimum you could look at JJI joists, although they may only offer 10-20mm max

The only way to achieve more headroom is a dormer window, but they add significantly to the cost.

Joists - My builder suggested exactly that and was going to look into it.  He's scheduled to visit sometime next week to do some more precise measuring.  Hopefully, I'll get a bit more info. then.

 

Dormer - I considered a full-width dormer right at the very start but thought there might be a risk of over extending our house.  Unless it was one large bedroom with a luxurious en-suite, the space created would be more appropriate to two bedrooms.  A six bedroom house would make it the largest on the street.  I may have missed an opportunity but I wasn't comfortable with the risk.

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Ummm - a steamy stripper..........

 

Did she become "ex" as a result?

You may think that. I couldn't possibly comment.

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Fire doors

 

I know the readers of this thread have a mixture of experience so apologies for those who know all this already.  I knew next to nothing about most of this a few years ago so I'm not claiming to be an expert but if by putting this into writing it helps others then that's great.  There's also the chance that I might have misunderstood something so please let me know or ask questions.

 

Once you add a third storey, fire regulations require a protected exit route.  Our house has a central hallway on the ground floor with stairs leading up to a landing and the exit route from the loft would be via these two areas.  So this means changing the doors on the landing and hallway to fire doors.  The original doors are the now ubiquitous moulded, panelled ones and the doors to bathrooms and cupboards do not need to be changed, therefore the simplest option was to find matching fire doors.

 

For anyone unfamiliar with fire doors they are commonly made from 40mm thick solid chipboard so they are heavy (around 2.5 times the weight of an ordinary hollow moulded door).  Intumescent strips are required around the top and sides.  These expand at around 200oC to create a smoke seal and can be recessed into the door or into the frame.

 

I fitted a fire door elsewhere in the house several years ago and bought a simple second hand door and a new frame which had a groove routed into the top and sides into which you slot the intumescent strips.  To avoid the cost, time and mess of replacing all the door frames my intention this time was to rout a groove into the doors.  I found some brand new (graded seconds) fire doors on ebay and ordered the sizes and numbers I required.  What I thought was a bargain price turned out to be even better.  When they arrived, the doors already had intumescent seals fitted, so no routing and no additional expense (around £7 per door) for seals!  What makes them seconds seems to be fairly trivial.  A couple of doors were missing tubular latches but I already had some of these in stock, there are one or two scratches but these are minor and easily touched up, and some corners are a little damaged which is also easily fettled.  The doors are also pre-finished to a good standard in satin white.  So, a little bit of effort and I have all the fire doors I need at £30.22 each which I'm very pleased about.

 

The hinges are a different shape and there are three per door to cope with the extra weight but it isn't too difficult to alter the door frames.  So the sequence for each door is: remove old door, remove door stops, chisel out new hinge recesses, reposition the latch to suit the slightly thicker door, refit the stops (after planing down if required), swap the handles over and then fill and paint the frames.

 

Inevitably, it is never as easy as it sounds since the existing frames are fitted at an assortment of angles and bow in and out all over the place.  One door frame in particular must have been fitted by a carpenter with one leg shorter than the other!

 

From what I can gather, door manufacturers these days often supply complete door sets so it ought to be easier to fit doors straight without trimming or bodging.

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I'm almost half way through so far without too much unnecessary drama.  (That'll be the kiss of death.)  I'm taking my time, not only so I don't mess up but so that I can fit in with the rest of the family.  For example, planing the frame and fitting the door to the room where my wife is working from home would be a touch inconsiderate and would impact my brownie points balance.

 

One of the remaining doors will require some fiddling about.  I measured the width of the opening at three different heights and got three different measurements.  I'm hoping I'll be able to plane enough from the frame to allow the door to fit and take out the dogs-hind-leg style variation at the same time.

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I have successfully planed the dog's hind leg.

 

No, no animal cruelty was involved.  Apart from a little sanding and undercoating of filler and bare wood, the last of the replacement doors is now fitted.  Well, when I say last, I'm not including the one from the hall to the kitchen but I am leaving that for a while pending a decision on hall flooring.  The hall, stairs and landing are currently carpeted but it is somewhat threadbare and due for replacement once the loft conversion and the attendant mess is out of the way.

 

I also still need to fit a new door at what will be the bottom of the loft stairs and a further slim cupboard door next to it.  That should be much easier than trying to squeeze doors into wonky frames as I have more control over the dimensions and straightness of the doorway.  It should also create significantly less dust the clearing up of which has been a major time-consuming factor for the replacement doors.

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Well, the builders visited today more or less as planned to do a final measure up and discuss a few details.  I am now expecting work to commence in less than two weeks.  Exciting!  :imsohappy: :)

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Say goodbye to your sanity

Too late!

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Well the windows arrived and some of them made it into the house before I spotted they weren't quite right.  Just out by a crucial single letter in the identifying code which meant they had the wrong kind of glass.

 

Hopefully replacements can be turned around quickly enough not to delay fitting.  I did check with the manufacturers a few weeks ago who confirmed what I wanted was in stock so unless they've sold them in the meantime I think I've allowed sufficient contingency.  Without a secure, weather tight storage area it was always going to be a balancing act with ordering lead times on any materials not kept in stock by suppliers.

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Builders' merchant tells me the correct windows will be with me on Friday.  So that should be fine.

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