Nether Madder and Green Soudley Rly

[teaky]

For the roof, you need the air gap above the insulation to allow the timber rafters to breath otherwise they will rot.  Similarly, the walls are permeable and moisture will condense on the inside face.  This too needs ventilation to allow the moisture to escape.

 

Your imagined 'cell' is an appropriate way to think of this.  One side of the insulation faces the cold and one side faces the warm.  The sockets breach this cell which is why you have the condensation problem but it sounds like the builder will resolve this.  Moisture in the room might be that it is still drying out.  I remember several years ago waiting for the plaster to dry out in my newly converted garage, I had a heater in there to help things along but the drying out seemed to pause.  The solution was to open the windows wide once or twice for a couple of hours at a time which was slightly counter intuitive since it let all the warmth out but the drying out finished off quickly thereafter.

 

Background ventilation is important too.  Your converted garage should have a small connection to the outside.  This can be via trickle vents above the windows or a simple pipe through the wall with covers on each end.  Just enough to permit a little air flow but too small to impact heating.

 

I confess that I haven't been following this thread.  Did the builders put down a damp proof membrane over the original garage floor?

[Martin S-C]

Hi Rob

 

There is no timber in the roof, so no worries there - its an aluminium frame supporting a corrugated asbestos roof. Below the aluminium frame a plasterboard false ceiling has been hung and within the rafters the space has been stuffed with fibre insulation.

 

Yes, I am more and more convinced that two small vents are needed, one each end to give a constant trickle of fresh air.

Over the last week I have been going through a programme several hours each day of cracking the windows ajar about 1.5cm and running the dehumidifier but still moisture (via condensate) is dribbling out of the power sockets and very large amounts of condensate is forming on the air-con exhaust pipe (inside which there is obviously cold air) so there is a moisture issue that isn't going away, even if I allow fresh air in to circulate.

 

Yes, damp proof membrane went atop the original concrete floor and beneath the new wooden floor. I'm assuming its not been ruptured!

Edited December 18, 2018 by Martin S-C

[teaky]

Hi Rob

 

There is no timber in the roof, so no worries there - its an aluminium frame supporting a corrugated asbestos roof. Below the aluminium frame a plasterboard false ceiling has been hung and within the rafters the space has been stuffed with fibre insulation.

 

Yes, I am more and more convinced that two small vents are needed, one each end to give a constant trickle of fresh air.

 

Over the last week I have been going through a programme several hours each day of cracking the windows ajar about 1.5cm and running the dehumidifier but still moisture (via condensate) is dribbling out of the power sockets and very large amounts of condensate is forming on the air-con exhaust pipe (inside which there is obviously cold air) so there is a moisture issue that isn't going away, even if I allow fresh air in to circulate.

 

Yes, damp proof membrane went atop the original concrete floor and beneath the new wooden floor. I'm assuming its not been ruptured!

That appears to cover most of it.  Sorting out the sockets will help.  What about the air space between the wall insulation and the concrete structure: is it ventilated e.g. linked to the air space above the ceiling insulation?

 

Putting in the two small vents at each end certainly won't do any harm.  It is probably worth making sure the holes for these vents are angled down towards the outside by a tiny degree just to encourage any condensation to flow in the right direction if it does form inside the ventilation tubes.  It is worth noting though that the exact location and shape of the vents isn't too critical.  Because it is attached to the house and is a habitable space, when I converted our garage it had to comply with Building Regulations.  There is just one window around 1.8m wide with a fixed central pane and two opening ones.  I fitted trickle vents above each of the opening panes and this was sufficient for a room of approximately 5m x 4m.

 

And don't forget that if you don't breath whilst you are in there you will limit the amount of moisture you add to the atmosphere. 

[chuffinghell]

.............And don't forget that if you don't breath whilst you are in there you will limit the amount of moisture you add to the atmosphere. 

that's a fair point 

Edited December 19, 2018 by chuffinghell

[Martin S-C]

Breathing might be the issue. I'll try and cut down on that. Taking that to its logical conclusion, if I never go in there again the problem goes away entirely!

Thanks for the input Rob, an especially Cunning Plan to angle the vent holes downwards towards the exterior. The garage is a concrete panel jobbie so we have [concrete panel - celotex sheet insulation - interior plasterboard wall]. The celotex sheet is in contact with the concrete and the plasterboard in contact with the celotex. As the celotex is air-permeable I am not too worried about how tightly packed together it all is. The celotex sheets stand between the vertical studding the plasterboard is fixed to, so at some points its [concrete panel - softwood studding - interior plasterboard wall]. Not a terribly thick insulation layer but the problem I was facing was the narrow width of the structure. Its only 8 feet wide internally and I asked that the absolute minimum of space be lost for the insulation and interior wall and the builders got this down so that its only 2.5" per side giving me 7 foot 7 inches of usable width for the model railway. Still tighter than I'd like but we cut the structure to the bare minimum. I am now sitting here worrying that that may have been a mistake and thicker insulation is really necessary...

 

At the top, the plasterboard interior wall sheeting is screwed to a horizontal batten hung from the aluminium roof trusses. This batten is (IIRC) hard up against the eaves so I am not sure how much air is able to circulate from the roof void via the eaves to the concrete walls although clearly some is as evidenced by the marked cold air flow coming in through the power socket holes.

 

Correct - the celotex lining is open at the eaves though. The eaves are also open to the outside air. I was never happy that the builders chose to leave this as it was. It would be best to have a solution that blocked the open eaves (to ambient air) while keeping air circulation gaps between roof space and wall.

[Nearholmer]

My gut feel is that the insulation thickness is fine, at worst it means that you will use more energy keeping the interior warm than if you had gone for a thicker lining.

 

I'm pretty much convinced that the issue is lack of enclosure, possibly combined with the need for it all to dry-out a bit more after 'wet trades'.

 

The only other 'failure mode' that I can think of, and please don't even consider this one until your builder has properly enclosed the room and fitted trickle-vents, is that the original concrete structure has 'gone porous'. Its mega-unlikely, but concrete can degrade to porosity, if badly made in the first place, and faced with very adverse conditions.

[RedGemAlchemist]

The only other 'failure mode' that I can think of, and please don't even consider this one until your builder has properly enclosed the room and fitted trickle-vents, is that the original concrete structure has 'gone porous'. Its mega-unlikely, but concrete can degrade to porosity, if badly made in the first place, and faced with very adverse conditions.

Oh, I can comment on that from experience. You should see some of the concrete in the yard I work in. It's obscene how badly made it is, and it's got more holes in it it than Swiss cheese.

[teaky]

I went back to the beginning of this thread.  After doing by best not to be sidetracked by some lovely modelling I arrived at post 212 which appears to show the structure.  The concrete panels have hollows in them which will not be filled with insulation and the horizontal timbers at the top of the frame appear to have gaps behind them.  These gaps, if they have not been stuffed with ceiling insulation, will connect the wall air spaces with the roof air space.  This is a good thing.  You want air to be able to move.

 

My garage is single skin brick with battens and framing fixed to that and infilled with PIR (Celotex) then overfaced with thinner PIR and plasterboard.  Although brick is a better insulator than the concrete panels you have and there is a larger air gap you aren't too far off with 75mm thick PIR.  Don't forget I was trying to hit a specific target U-value as per the Building Regulations whereas you are just trying to make a hobby room more comfortable.  The amount of insulation you have will still do the job, especially since you are probably not going to be keeping the room at as high a temperature as, say, your living room.  There are plenty of houises around with less wall insulation than you have in your converted garage.

 

I don't know much about the porosity of the concrete panels but part of the reason for having an air space between a brick wall and the PIR insulation is because brick is permeable and condensation can form on the outer foil face of the PIR.  The air space allows it to escape.  You don't need a howling gale flowing through just nothing to impede the natural interchange of air.

 

Sealing everything up tight is exactly what you don't want.  That leads to moisture getting trapped in the structure which leads to rot.  The last bit of building work I did was to convert our loft and the Regulations are clear on the importance of air gaps between the rafter insulation and the tiles.  So much so that I had to add extra vents at the eaves and towards the ridge as part of the build.  I suppose the best way to think about it is that your garage concrete wall panels, roof and concrete base with DPM form a weatherproof box.  Inside this box you create another insulated box which is your room.

 

I suggest you keep doing what you are doing to slowly dry out the room (there's lots of moisture in timber and even more in the plaster) and let the builder insulate the sockets and put in some room vents (background ventilation).  If you still have the condensation after that then it is time to look at something not being right.  I think you are worrying unnecessarily though.

[DonB]

quote :- "I suggest you keep doing what you are doing to slowly dry out the room (there's lots of moisture in timber and even more in the plaster) and let the builder insulate the sockets and put in some room vents (background ventilation).  If you still have the condensation after that then it is time to look at something not being right.  I think you are worrying unnecessarily though."

 

 Additional moisture will have been added by the modern water-based paint. You commented earlier about the poor coverage and implied a need for a second coat application, how many litres of paint did you eventually use? -(not expecting / needing an answer, just indicating a potential source of moisture).

 

Hope it gets sorted soon

Edited December 19, 2018 by DonB

[Martin S-C]

The concrete panels have hollows in them which will not be filled with insulation and the horizontal timbers at the top of the frame appear to have gaps behind them.  These gaps, if they have not been stuffed with ceiling insulation, will connect the wall air spaces with the roof air space.  This is a good thing.  You want air to be able to move.

 

My garage is single skin brick with battens and framing fixed to that and infilled with PIR (Celotex) then overfaced with thinner PIR and plasterboard.  Although brick is a better insulator than the concrete panels you have and there is a larger air gap you aren't too far off with 75mm thick PIR.  Don't forget I was trying to hit a specific target U-value as per the Building Regulations whereas you are just trying to make a hobby room more comfortable.  The amount of insulation you have will still do the job, especially since you are probably not going to be keeping the room at as high a temperature as, say, your living room.  There are plenty of houises around with less wall insulation than you have in your converted garage.

 

I don't know much about the porosity of the concrete panels but part of the reason for having an air space between a brick wall and the PIR insulation is because brick is permeable and condensation can form on the outer foil face of the PIR.  The air space allows it to escape.  You don't need a howling gale flowing through just nothing to impede the natural interchange of air.

 

Sealing everything up tight is exactly what you don't want.  That leads to moisture getting trapped in the structure which leads to rot.  The last bit of building work I did was to convert our loft and the Regulations are clear on the importance of air gaps between the rafter insulation and the tiles.  So much so that I had to add extra vents at the eaves and towards the ridge as part of the build.  I suppose the best way to think about it is that your garage concrete wall panels, roof and concrete base with DPM form a weatherproof box.  Inside this box you create another insulated box which is your room.

 

I suggest you keep doing what you are doing to slowly dry out the room (there's lots of moisture in timber and even more in the plaster) and let the builder insulate the sockets and put in some room vents (background ventilation).  If you still have the condensation after that then it is time to look at something not being right.  I think you are worrying unnecessarily though.

The hollows in the concrete panels are where the celotex sheeting goes. The upper and lower wall battens were fixed to the ribs of the concrete panels so the celotex could be slid in between. The studding was attached to the top and bottom battens and the plasterboard walls to the studding. I'm happy that there is both air circulation and insulation between plasterboard wall and concrete panel though its not quite as you suggested in your first paragraph. I have edited a photo to try and show the arrangement with the vertical studding in orange, the upper batten in red and the ribs of the concrete panels in light brown. The green arrows indicate the recesses between the concrete ribs where celotex sheet has yet to be "stuffed in" and of course the top batten is proud of this area, being screwed to the ribs, so yep, some air is allowed from the celotex sheets up into the eaves and roof void.

 

 

Post #207 shows the battens and studding. With air from the eaves able to circulate past the top batten.

 

The fibre roof roll insulation was of similar form to the underfloor insulation you can see in the photo above.

 

"These gaps, if they have not been stuffed with ceiling insulation..."

 

I think so. I went back through my set of photos of the build and the one below shows the roof void between the new rafters being stuffed with insulation fibre so it looks like there is space for air to circulate there, though I didn't pay close attention to quite how much insulation was packed into the spaces. I simply trusted the builders to do it correctly. I will be horrified if they haven't!

 

 

"You don't need a howling gale flowing through just nothing to impede the natural interchange of air."

 

I really do not know if I have that. It will be expensive to pull the walls off and look now...

 

Thanks for all your continuing help and advice.

[Martin S-C]

Don - I am halfway through my third 5 litre tin. I expect 13 to 14 litres of paint will have gone in there by the time its all painted sufficiently.

[teaky]

The hollows in the concrete panels are where the celotex sheeting goes. The upper and lower wall battens were fixed to the ribs of the concrete panels so the celotex could be slid in between. The studding was attached to the top and bottom battens and the plasterboard walls to the studding. I'm happy that there is both air circulation and insulation between plasterboard wall and concrete panel though its not quite as you suggested in your first paragraph. I have edited a photo to try and show the arrangement with the vertical studding in orange, the upper batten in red and the ribs of the concrete panels in light brown. The green arrows indicate the recesses between the concrete ribs where celotex sheet has yet to be "stuffed in" and of course the top batten is proud of this area, being screwed to the ribs, so yep, some air is allowed from the celotex sheets up into the eaves and roof void.

 

Image3.png

 

Post #207 shows the battens and studding. With air from the eaves able to circulate past the top batten.

 

The fibre roof roll insulation was of similar form to the underfloor insulation you can see in the photo above.

 

"These gaps, if they have not been stuffed with ceiling insulation..."

 

I think so. I went back through my set of photos of the build and the one below shows the roof void between the new rafters being stuffed with insulation fibre so it looks like there is space for air to circulate there, though I didn't pay close attention to quite how much insulation was packed into the spaces. I simply trusted the builders to do it correctly. I will be horrified if they haven't!

 

Image4.png

 

"You don't need a howling gale flowing through just nothing to impede the natural interchange of air."

 

I really do not know if I have that. It will be expensive to pull the walls off and look now...

 

Thanks for all your continuing help and advice.

If the vertical battens don't coincide with the concrete panel ribs then that sounds even better because there is air space behind the timber too.  If that is correct then it might also be an indication that the builders thought about the air gap and that they also thought to connect it to the eaves.

[teaky]

Don - I am halfway through my third 5 litre tin. I expect 13 to 14 litres of paint will have gone in there by the time its all painted sufficiently.

Ah, this is me coming in part way through again.  So that implies that the plaster is already dry then if you're painting.  I assume it is emulsion suitable for new plaster and you're not sealing any remaining moisture in with something like a vinyl emulsion?

[Martin S-C]

I understand the intention was to attach the studding to the ribs of the concrete panels so that the maximum depth was then available for the celotex. The idea being that maximising celotex depth this way meant we could get away with studding of smaller dimensions and so encroach on the final internal room width as little as possible. Not every stud may have coincided with a rib however.

 

The plasterboard wasn't entirely plastered but received only a skim over the joins and screw heads, even so I left this about 2 weeks before painting. The paint was extremely basic water based emulsion so not vinyl.

 

EDIT: Post #358 on page 15 shows the extent of the plastering.

Edited December 19, 2018 by Martin S-C

[BWsTrains]

I understand the intention was to attach the studding to the ribs of the concrete panels so that the maximum depth was then available for the celotex. The idea being that maximising celotex depth this way meant we could get away with studding of smaller dimensions and so encroach on the final internal room width as little as possible. Not every stud may have coincided with a rib however.

 

The plasterboard wasn't entirely plastered but received only a skim over the joins and screw heads, even so I left this about 2 weeks before painting. The paint was extremely basic water based emulsion so not vinyl.

 

EDIT: Post #358 on page 15 shows the extent of the plastering.

None of that will be an issue on the scale you're suffering.

 

Water in plaster is mostly used for the reaction as it sets, the slight xs evaporates quickly. Any paint these days is water based and the finished film is water porous so evaporation will happen.

You'd know if substrate beneath was too wet, paint wouldn't stick properly to the surface.

[Martin S-C]

The builder contacted me today and the remedial work on the electrics and the investigation into the dampness issues won't be started until January.

[Martin S-C]

Over the last few weeks I have been having a bit of a think. I've not been on RMWeb very long and if there's a thread I feel most at home in, it's James' thread where he is modelling an Edwardian fictional railway in Norfolk and a whole crowd of eclectic folks discuss all things relating to Edwardian railways and society (and many things that are not at all related). There is a lot of interesting style and mood thinking going on over there and its rubbing off on me.

One feature of my own fictional world that has risen uppermost in my mind is this merging of fact and fiction, of the serious and the whimsical. Whimsey is good, I have a lot of time for it and my modelling has never been too serious. I could never be a David Jenkinson, a Barry Norman or build a layout like Heckmondwike. I have always embraced a big helping of fantasy in my modelling and its the reason I embarked on what I'm doing now, rather that set out on a course of painstaking research for a particular prototype location and moment in time (and built to finer standards).

Having defended my preferences thus far I think what is bothering me is the amount of whimsey in my layout, or rather its style. There is a good deal of double entendre in several of the names and a recent discussion on here about industry names brought forth a suggestion or two that bothered me as they were close to a kind of "line in the sand" of decency that I felt uncomfortable getting close to.

I have therefore taken the decision to rework the naming of my model and several of the stations and industries on it. Place names like "Borrocks" and "Great Shafting", I have decided, must go. There is traditional English schoolboy humour in such names but I've decided its not what I want to live with if this layout lasts me out through retirement. They were humorous at first, but such names grate on me already.

A map of fictional place names in Britain derived from books, films and models was posted recently on a Facebook group I am a member of and several of these, located in or near the Hereford-Mitcheldean-Gloucester triangle confirmed my preference for some name changes. As I have the initials for Great Shafting now fixed in my freelance rolling stock livery the letters "G S" were a must and for now I'm working with the town name of Great Sandford. Borrocks for the moment I am replacing with Mitcheldean as I want some way to fix the model into the location its supposed to be, even though my Mitcheldean will bear absolutely no similarity to the real place, nor any railway that served it or went hear it. Mitcheldean is a working title only for now, it may change... it may not. We'll see how I feel about it in the new year.

The Deep Shafting Colliery will be the Deep Sandford Colliery and other fictional places in the region will be incorporated into several of my industry names.

After a fairly dry patch lasting 2 or 3 weeks and brought on by my disappointment over problems in the garage conversion I stopped modelling but today for the first time in a while I had the urge to model again so I plan to tackle a few more wagons over the Christmas break and may even get around to lining those dratted coaches.

 

Mention of whch brings me neatly around to wishing anyone reading this a very happy winter break and a prosperous and successful 2019.

 

Edited December 23, 2018 by Martin S-C

[Northroader]

I can appreciate where you’re coming from, and what you’re doing makes great sense, or would if it didn’t have some whimsy written in to it, which makes sense anyway. Hope the problems with the conversion are sorted soon, and you make great progress next year.

[Annie]

I will be completely honest and say that I've never had any time for smutty humor and while I'm happy to be a whimsical railway modeller I've never considered using place names or industry names that have a thinly veiled impolite meaning.  So I guess what I'm saying Martin is that I applaud your decision and I'm sure that you won't regret it as work on your layout proceeds.

 

There's an on-line English place name generator that's intended for folk who are playing RPG type games, but is perfectly fine for railway modellers in search of a name for their imaginary town or village.  I've used it to find place names to use on my imaginary PO wagons, though sometimes the place name generator will turn up a real name so it's worth checking if it's a fictitious name you're after.

 

I hope the problems with your new railway room will be quickly sorted come the new year as I can very much appreciate the disappointment you must be feeling.  Don't lose heart though not now that you are so close.

 

And yes I agree James's West Norfolk Railway thread is very inspiring with all manner of wonderful nuggets of obscure, but fascinating information being turned up on a daily basis.  It certainly helped me to finally step back in time past 1924 and stop being a half hearted Big 4 modeller and actually get on with doing something worthwhile.  And it certainly was an influence when I started to put together ideas for my own imaginary freelance tramway. 

[Martin S-C]

Great Shafting is no more and will be Great Soudley from now on, there being a Soudley in the SE area of the Forest.

Mitcheldean, nee Borrocks is probably going to be Puddlebrook.

[Annie]

'Puddlebrook', - now there's a good whimsical place name.

[Martin S-C]

Its a real place, a few miles from Mitcheldean in the Hereford direction. I saw it on the map and knew it had to be that one. I was really just poring over a map looking for suitable names in the general locality. Other industry names will come from fictional literature set in the region.

"Cat Got Your Tongue" halt was amusing but too much of a mouthful. There was a Catsbrain House near the line on the Highworth Branch (which I mentioned before I researched for a train simulator route) and the line was crossed by a footpath to it carried on an overline bridge which became known as Catsbrain Bridge. I have therefore chosen to rename Cat Got Your Tongue Halt to Cat's Paw Halt, partly to retain the catty reference (I'm a cat fan) and partly to make it sound more like Catsbrain.

 

Other stations and towns are unaffected.

Edited December 24, 2018 by Martin S-C

[Nearholmer]

For what little it’s worth, I’m no great fan of overly rude fictional place names either, although some real ones can have pretty earthy connotations.

 

The place name generator I tried out of interest, and it’s sort of OK, but it, naturally, fails on things like word endings that are typical to particular parts of the country. The fairly hard line that cuts off ‘by’ endings is an instance; where the Vikings stopped, it stopped.

 

Was there an author who set their books in your chosen locale? Can save a lot of head-scratching.

[Martin S-C]

There are several authors whose fiction is based around this area - Eleanor Brent-Dyer, Phil Rickman and Robert Holdstock that I know of. Sir Arthur Conan-Doyle set one of his Sherlock Holmes stories in the Forest region. I've pulled several place names from these authors for industries on the layout. It may be a tenuous link but its one way of tying things together.

[dunwurken]

Great Shafting is no more and will be Great Soudley from now on, there being a Soudley in the SE area of the Forest.

Mitcheldean, nee Borrocks is probably going to be Puddlebrook.

Martin

Just in case you decide Puddlebrook is not quite right and decide on Puddlebridge I would advise you the Edinburgh & Lothians MRC has an O gauge layout by that name, an actual bridge at Ormiston at the junction of the former Gifford and Garvald Light Railway the NBR branch to Macmerry. As a further aside the next signal box back up the line was Bog Siding!

Malcolm