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Best type of insulation to use GRP


Tillymint

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Hi, we've just purchased an old Burland 27 GRP cruiser, it's stripped back and we want to insulate it before recarpeting the walls.  We don't mind spending a little, but we have to be realistic as the boat has limited value.  Preferably something self adhesive if possible so we can just cut and stick, but I'm struggling with finding what I should be using and how thick. 

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7 hours ago, Tillymint said:

Hi, we've just purchased an old Burland 27 GRP cruiser, it's stripped back and we want to insulate it before recarpeting the walls.  We don't mind spending a little, but we have to be realistic as the boat has limited value.  Preferably something self adhesive if possible so we can just cut and stick, but I'm struggling with finding what I should be using and how thick. 

Also probably something strong enough to hold the cabin side and roof lining in place. I suspect it may need you to baton the roof and cabin sides so you can stick up some slab insulation. There price would suggest flame resistant expanded polystyrene sheets 25 to 50 mm thick. The price would probably also rule out Thinsulate.

 

I am interested in what others come up with because in my experience few GRP boats a insulated.

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Our GRP cruiser is insulated behind the wall panels with 1" 'silvered bubble wrap'

 

Like bubble wrap but is silver-foil.

It is very effective, but I guess it depends if you already have wall panelling, or if the carpet is just glued onto the GRP hull.

 

It is the sort of stuff used behind domestic radiators but MUCH bigger bubbles - but I guess if you have limited space then the normal radiator 'stuff' would be some improvement.

 

Are you planning to liveaboard ?

 

Edit to add :

 

This sort of stuff - but I don;t know what size this is :

 

https://www.ebay.co.uk/itm/Loft-insulation-Aluminium-foil-Bubble-Wrap-100sqm-2-foil-1m-wide-B-Grade-/362279831328

 

 

Edited by Alan de Enfield
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We don't intend to live aboard, but we wilk be using it 3 seasons quite a bit, spring and autumn evenings can get chilly, so I thought some sort of insulation would cut back a bit on need for heating.  I was looking at the foil type stuff, just wasnt sure if it was the right stuff, I wouldnt want to make a mistake off the bat.  It needs to be flexible for all the curves.  Id prefer self stick but can buy a fixative.

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29 minutes ago, Tillymint said:

We don't intend to live aboard, but we wilk be using it 3 seasons quite a bit, spring and autumn evenings can get chilly, so I thought some sort of insulation would cut back a bit on need for heating.  I was looking at the foil type stuff, just wasnt sure if it was the right stuff, I wouldnt want to make a mistake off the bat.  It needs to be flexible for all the curves.  Id prefer self stick but can buy a fixative.

Use the foil stuff, it will help, but remember that to work it is really based on reflectivity and if you glue it to the hull and then stick carpet on top it will only work on the conductive level. To be reflective it needs an air gap.

 

Do you have wall panels, or carpet glued onto the hull ?

 

If you have wall panels, then it should work OK. 

Glue it onto the hull and mount the wall-panels on battens leaving a 1" gap between the back of the panel and the surface of the 'foil'.

 

 

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Just a thought - Cruisers tend to have very large, single glazed, windows - this is a big source of hear loss. Obviously curtains help but we have found that for 'cold weather' usage having 'canvas shutters' on the outside reduces the heat loss immensely.

 

Only takes a couple of minutes to fix them / take then down night & morning (they are on 'poppas')

Versatility-35-36.jpg

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26 minutes ago, Alan de Enfield said:

Just a thought - Cruisers tend to have very large, single glazed, windows - this is a big source of hear loss. Obviously curtains help but we have found that for 'cold weather' usage having 'canvas shutters' on the outside reduces the heat loss immensely.

 

Only takes a couple of minutes to fix them / take then down night & morning (they are on 'poppas')

I'm in the process of looking at little GRP boats at the moment and this snap fastener set up is very interesting to me could you explain how you attach the fasteners to the boat, is it an aluminium window frame and you glue it on that and if so what do you use, did you make the canvas shutter your self?

 

And one last one does it help to cut down condensation?

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10 hours ago, Tillymint said:

Hi, we've just purchased an old Burland 27 GRP cruiser, it's stripped back and we want to insulate it before recarpeting the walls.  We don't mind spending a little, but we have to be realistic as the boat has limited value.  Preferably something self adhesive if possible so we can just cut and stick, but I'm struggling with finding what I should be using and how thick. 

If your looking at Insulation slabs; then these may be cheaper https://www.secondsandco.co.uk,  however I'm guessing you will only need a small amount so delivery probably cost more than just going to a local b&q place.

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20 minutes ago, Tumshie said:

I'm in the process of looking at little GRP boats at the moment and this snap fastener set up is very interesting to me could you explain how you attach the fasteners to the boat, is it an aluminium window frame and you glue it on that and if so what do you use, did you make the canvas shutter your self?

 

And one last one does it help to cut down condensation?

Press studs.

The 'base unit' screws into the GRP (with a dab of silicone behind it), or there are other methods (like a rivet)

The 'other' part is simply placed onto the canvas, hit with a small 'punch' that comes with the kit which punches thru' the fabric and fixes the top half of the 'poppa' by rolling the edges over.

 

I bought a kit from Aldi for a couple of pounds.

 

This pic may show better - 2 side windows, and a big cover for the front 3-windows.

Also good for when you leave the boat, protects the windows, saves the Sun bleaching internal fabric etc etc.

 

 

 

Easy-peasey (if you can measure and cut the fabric to the correct size.

 

 

 

 

 

CAM00020.jpg

Edited by Alan de Enfield
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14 minutes ago, Alan de Enfield said:

Press studs.

The 'base unit' screws into the GRP (with a dab of silicone behind it), or there are other methods (like a rivet)

The 'other' part is simply placed onto the canvas, hit with a small 'punch' that comes with the kit which punches thru' the fabric and fixes the top half of the 'poppa' by rolling the edges over.

 

I bought a kit from Aldi for a couple of pounds.

 

This pic may show better - 2 side windows, and a big cover for the front 3-windows.

Also good for when you leave the boat, protects the windows, saves the Sun bleaching internal fabric etc etc.

 

Easy-peasey (if you can measure and cut the fabric to the correct size.

Thank you, Alan. That's fantastic. :D

Just now, Alan de Enfield said:

Sorry - missed that question.

 

Yes as the window is not 'cold' then the warm air does not condense on it.

That's even better. Brill.

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I don't think there is much insulation  in my cruiser.

Condensation is limited to colder months and is primarily only an issue occasionally and is generally on aluminium window frames and glass.

Plenty of ventilation does help at any time of year and sometimes heating on with window ajar may be necessary. 

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1 hour ago, MartynG said:

I don't think there is much insulation  in my cruiser.

Condensation is limited to colder months and is primarily only an issue occasionally and is generally on aluminium window frames and glass.

Plenty of ventilation does help at any time of year and sometimes heating on with window ajar may be necessary. 

If you start dismantling things and prodding around the boat you will find there is no insulation at all. But what there is, is an air gap between the outer surface and the inner liners. This air gap acts to insulate the boat.

 

With the correct amount of ventilation we get no condensation when onboard. We leave the windows open and the roof hatch cracked open whenever we are onboard as we can not abide a damp environment. Even with the extra moisture the dog is breathing out we don't find we are having troubles with condensation. It has not been at it's coldest yet of course so time will tell if we need to take any extra measures during mid winter. 

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35 minutes ago, Naughty Cal said:

This air gap acts to insulate the boat.

The R factor for air is 1.01 (effectively 'nothing')

You need to add something into the air space to get any improvement in R factor.

 

R-value is the ability of an insulation to resistance to heat flow. The higher the R-value, the greater the insulating effectiveness. In limited-size spaces, you want a higher r-value to maximize the insulation in the space.

That being said, dead air alone isn’t super effective as an insulator. Instead, adding a low emittance (low-e) material/surface on at least one side of an air gap results in a better performing system. A great example of this is radiant barrier foil; for example, AtticFoil® has an emissivity of 0.03%, meaning it only allows about 3% of radiant heat to pass through it. Therefore, adding radiant barrier foil in an enclosure can reduce the radiant heat to near zero and the air space aids the foil in being able to accomplish that because radiant barriers require an air space. It should be noted that while this type of installation is great at reducing the heat gain for a non-conditioned structure (like a shed/garage/etc.), if the space is being heated and cooled, you will need to add additional r-value without compromising the air gap since radiant barrier foil doesn’t replace traditional insulation.

Bottom line: a dead air space on its own isn’t an effective form of insulation, but when paired with a reflective radiant barrier, the overall performance of the wall is greatly improved.

 

 

If air was a good insulator we wouldn't feel the warmth of the Sun. !!!

 

Edited by Alan de Enfield
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Not all parts on ours is double skinned. Some bits it just vinyl with a thin foam padding. 

I guess we should try using our mid cabin for sleeping over in cold weather  as it is better insulated being beneath the main helm and saloon.

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5 hours ago, Alan de Enfield said:

Our GRP cruiser is insulated behind the wall panels with 1" 'silvered bubble wrap'

 

Like bubble wrap but is silver-foil.

I

 

 

50 minutes ago, Alan de Enfield said:

The R factor for air is 1.01 (effectively 'nothing')

You need to add something into the air space to get any improvement in R factor.

 

If air was a good insulator we wouldn't feel the warmth of the Sun. !!!

 

What is inside the bubble in the bubble-wrap insulation?

 

Air is a poor conductor - which is why most insulation materials have a good deal of air in them.  And string vests.  It is not so good at obstructing radiation (which is handy, if you want to feel the warmth of the sun).  It is also prone to convection which means insulation materials have to incorporate barriers.  

 

 

 

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1 hour ago, MartynG said:

Not all parts on ours is double skinned. Some bits it just vinyl with a thin foam padding. 

I guess we should try using our mid cabin for sleeping over in cold weather  as it is better insulated being beneath the main helm and saloon.

Not sure why yours would be built any different to ours but even the ceilings are double skinned with a smaller gap between the outer and the inner liner.

 

You can see the gap if you take any speakers, hatches, windows etc out.

1 hour ago, Alan de Enfield said:

The R factor for air is 1.01 (effectively 'nothing')

You need to add something into the air space to get any improvement in R factor.

 

R-value is the ability of an insulation to resistance to heat flow. The higher the R-value, the greater the insulating effectiveness. In limited-size spaces, you want a higher r-value to maximize the insulation in the space.

That being said, dead air alone isn’t super effective as an insulator. Instead, adding a low emittance (low-e) material/surface on at least one side of an air gap results in a better performing system. A great example of this is radiant barrier foil; for example, AtticFoil® has an emissivity of 0.03%, meaning it only allows about 3% of radiant heat to pass through it. Therefore, adding radiant barrier foil in an enclosure can reduce the radiant heat to near zero and the air space aids the foil in being able to accomplish that because radiant barriers require an air space. It should be noted that while this type of installation is great at reducing the heat gain for a non-conditioned structure (like a shed/garage/etc.), if the space is being heated and cooled, you will need to add additional r-value without compromising the air gap since radiant barrier foil doesn’t replace traditional insulation.

Bottom line: a dead air space on its own isn’t an effective form of insulation, but when paired with a reflective radiant barrier, the overall performance of the wall is greatly improved.

 

 

If air was a good insulator we wouldn't feel the warmth of the Sun. !!!

 

It is however better then just a single skin of grp with no air gap.

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5 hours ago, Alan de Enfield said:

Just a thought - Cruisers tend to have very large, single glazed, windows - this is a big source of hear loss. Obviously curtains help but we have found that for 'cold weather' usage having 'canvas shutters' on the outside reduces the heat loss immensely.

 

Only takes a couple of minutes to fix them / take then down night & morning (they are on 'poppas')

Versatility-35-36.jpg

What a fantastic idea

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9 minutes ago, MartynG said:

Glass Reinforced Plastic

Actually GRP =  Glass Reinforced Polyester (which 'Joe Public' has bastardised into Glass Reinforced Plastic)

There was a detailed thread about this a few months ago.

 

GRP started out as glass reinforced polyester in the 60s and 70s but it's use has drifted into the word plastic. The GRP we make boats out of however is not plastic. Look up the definition of plastic. It is a material that can be moulded at higher temps. GRP cannot be moulded. Wikipedia is wrong in saying it is a type of plastic. It's just everyone and his brother has decided the word plastic can be used for things it isn't...including Wikipedia.

There is even one site on tinternet that says there are two types of plastic - thermoplastics and thermosets!!! Rubbish. 

Another clue is that epoxy laminates i.e. GRP but with epoxy instead of polyester are never called GRP. They are called epoxy laminates or epoxy composites. 

No, while the world may think GRP is a type of plastic, GRP is most definitely not a plastic as plastics are by definition mouldable above their softening point. GRP is not mouldable once it is cured. Now, the clever ones of you out there may say it is plastic before cure.......and yes, I would agree, the unsaturated polyester resin dissolved in styrene is a plastic, but once cured, it looses its plastic nature.... never to return.... and becomes a thermoset.

In the 80s, the car manufacturers introduced glass filled polypropylene for bumpers. They never used the word GRP but they would have if GRP meant plastics. 

Plastics and thermosets have been my job for the last 48 years.?

Its nice to be different.

 

 

Edited by Alan de Enfield
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