[ChrisK]

Hi new to the forums and need a question answered

Is it better to put polystirene sheets in between the roof beams or use rolls of insulation from a diy store before boarding over the top of it

Sorry next question do I need to keep gaps for air flow in the roof or can I box it all in

 

[Rhiwderin_Ray]

Hi Chris. You can get foil covered foam insulation that is ideal leave a gap top and bottom for airflow.

 

[ChrisK]

Thanks for the quick reply Rhiwderin

Can I not box in with wood or do i need to leave a gap in the wood top and bottom as well as the insulation

What kind of wood is cheap but does the job to cover the insulation

Also how thick and what kind of wood should I use to board up the floor

 

[Rhiwderin_Ray]

You should use plasterboard to cover it. Too much wood is a fire risk.

First check that your joists can support your weight without cracking the ceilings. Get a builder / surveyor to check it out. You can get DIY flooring sheets at any big outlet, the thicker the better.

 

[John Webb]

I agree with Ray - use plasterboard. Wood of any sort is too hazardous and will rapidly spread fire should it start anywhere in the loft. There are some foil-backed/fronted bubble sheets which can be used with a reasonably low 'surface spread of flame' rating - that's what I've done in my loft but without the insulation behind. That leaves the space behind free for good airflow.

Regards,
John Webb
(28 years in Fire Research!)

 

[ChrisK]

Thanks again for the quick reply

Been wanting to set up a track in my loft for some time once I get the basics sorted i.e floor and insulation then I can start thinking anbout base boards and track design

 

[Makemineadouble]

Celotec is the material you slide between the roof trusses
50mm is ideal it's easy to cut with a saw and has foil one
side. Covering with plaster board makes your loft fairly
dust free and you have a nice air gap behind. I painted mine
to give me good reflective light.

 

[Brake Compo]

Have recently made the second of the four separate loft areas in my house usable and improved the insulation (although unfortunately not for a model railway). I used 100mm Celotex between the joists - this should be spaced 50mm off the underside of the roofing felt (by nailing 2x1 to the sides of the rafters) to leave an air circulation space above above it. A vapour barrier (plastic sheet) needs to be installed between the Celotex and the plasterboard to prevent condensation rotting the joists (I also gave them a good Cuprinoling first as their treatment appeared suspect/non existent in this part of my roof). It is also important to knock out any insulation in the eaves that would prevent air circulation above the Celotex, if one does not want to the roof timbers to go rotten - this (and the need for a vapour barrier) is something that applies to all insulation applied at rafter level.

 

[34C]

Unless this is your outright owned property, and you don't bother to insure the structure, then there are other parties who should be consulted before what constitutes a material change is made to the building. Because of the variation in construction in roofs, I would strongly advise that employing a surveyor to spec what is proposed to be done is the first step. A surveyor will be able to assure any of insurance company, mortgager or landlord (whichever apply to your situation) that the proposed changes are not detrimental and meet whatever are the applicable standards.

Present creakiness of the financial sector is going to impinge on insurance: claims are increasingly going to be subject to search for any action invalidating wholly or partly the terms of the policy. Better to have all one's ducks in a row so that if the worst happens there is no opening for a claims adjuster to get busy with. Just seen someone have their claim rejected for damage consequent on a bloke who fell through a ceiling: he was installing Velux type roof lights, and the insurer quite rightly refused the claim because the policy required prior notification ahead of material changes to the structure...

 

[PAPPA.B]

Some things to think on, aside from the insurance issue .I would avoid nailing anything to the rafters use screws as nailing could cause tiles or slates to come loose hth.Jim

 

[Brake Compo]

QUOTE (PAPPA.B @ 22 Jun 2012, 20:35) <{POST_SNAPBACK}>I would avoid nailing anything to the rafters use screws as nailing could cause tiles or slates to come loose hth.Jim

Good point - all of the guides do advise using screws into the rafters for this very reason - in my case the house was totally re-roofed in the 1970s, topped with heavy interlocking clay tiles, which I judged would not come loose with the thin 1 1/2" nails that I used. But yes if one has a slate roof I would certainly not recommend this approach.

 

[Brake Compo]

QUOTE (34C @ 22 Jun 2012, 09:50) <{POST_SNAPBACK}>Unless this is your outright owned property, and you don't bother to insure the structure, then there are other parties who should be consulted before what constitutes a material change is made to the building. Because of the variation in construction in roofs, I would strongly advise that employing a surveyor to spec what is proposed to be done is the first step. A surveyor will be able to assure any of insurance company, mortgager or landlord (whichever apply to your situation) that the proposed changes are not detrimental and meet whatever are the applicable standards.

Present creakiness of the financial sector is going to impinge on insurance: claims are increasingly going to be subject to search for any action invalidating wholly or partly the terms of the policy. Better to have all one's ducks in a row so that if the worst happens there is no opening for a claims adjuster to get busy with. Just seen someone have their claim rejected for damage consequent on a bloke who fell through a ceiling: he was installing Velux type roof lights, and the insurer quite rightly refused the claim because the policy required prior notification ahead of material changes to the structure...

While this is good advice, which I certainly would not wish to disagree with; my understanding is that loft insulation is not subject to Building Control, and would only become so if one were either converting the loft into a habitable room, or one were making structural alterations (either of which might have been the case in the Velux example). I would therefore suggest that an insurer might find it difficult to wriggle out of invalidating a claim where works outwith the scope of Building Control have been carried out.

What insurance certainly would not cover, however, is damage caused by incorrectly executed works (e.g. rafter rot caused by poorly installed insulation).

 

[patrick draper]

I used my loft for 27 years and only moved out of it due to health reasons last year. I moved to a larger house. My ex loft was tiled with a pitch type liner under the tiles. It was a bit draughty when wndy and hot in the summer and too cold in the winter. If you are intending staying in the property then have a loft conversion done by a professional, they are expensive as they need fire doors on all rooms nearby. I had mine priced up but the geometry of the roof made it impossible. You need to have a surveyor look at it and he will draw up plans that can be adhered to, the local council also will require you to submit the plans for planning permission and then , if passed, the building inspector will inspect the conversion, Sounds a lot doesn't it. It is. Do I sound like someone who has been there? I am.

 

[Andrew Rolland]

I used Kingspan Thermapitch TP10 75 mm thick insulation which I fitted between my rafters. Shop around for this as B&Q wanted about £45 a board 2.4m x 1.2m but I got it for just over £30 per board. I needed 24! Made a huge difference, heating bills have dropped and the loft is a constant temp now.

I retained the Kingspan with small battens, although I cut them so they were a snug fit between the rafters so they are almost self supporting. My rafters are 110mm deep so there is plenty of space for air to circulate between the rear of the kingspan and the underside of the roofboards.

The Kingspan Insulation website gives you good examples of how to fit these boards.

 

[PAPPA.B]

Hi King span and Celotex are two of quite afew makes of the same type there are others .If your cheeky enough look for companies selling 2nds damaged sheets you might save a few pounds if you don't mind spending time sorting through whats good or bad.By the way Insurance should not be affected by insulation but putting floorboards and fixing plasterboard etc may. Ventilation of the timbers is important, also ventilation for you too it could get stuffy.Getting some good professional and costing advice before you start is very good advice. I hope this does not put you off building a layout what ever you decide good luck .Jim

 

[ChrisK]

Did not think about air to the floorboards to be honest what if I just boarded straight down the middle of the loft with either end open?
I have a fairly new house finished in 2007 A frame style 8ft by about 16 ft wide there is room for a railway with hard work plenty of time and dedication just want to get the basics right as a platform to go from

 

[gexema]

Unless this is your outright owned property, and you don't bother to insure the structure, then there are other parties who should be consulted before what constitutes a material change is made to the building. Because of the variation in construction in roofs, I would strongly advise that employing a surveyor to spec what is proposed to be done is the first step. A surveyor will be able to assure any of insurance company, mortgager or landlord (whichever apply to your situation) that the proposed changes are not detrimental and meet whatever are the applicable standards.

Present creakiness of the financial sector is going to impinge on insurance: claims are increasingly going to be subject to search for any action invalidating wholly or partly the terms of the policy. Better to have all one's ducks in a row so that if the worst happens there is no opening for a claims adjuster to get busy with spray foam insulation maryland. Just seen someone have their claim rejected for damage consequent on a bloke who fell through a ceiling: he was installing Velux type roof lights, and the insurer quite rightly refused the claim because the policy required prior notification ahead of material changes to the structure...

I have an old, cold house and the loft has a couple of rolls of what looks to be cheap insulation. I'm looking to put more down but I'm wondering if there's a point whereby adding extra doesn't actually help? I don't mind spending a good few hundred on a lot of rolls if each one will help, but would obviously rather not if there's very little difference between say 2 or 3 layers. Any thoughts/ info would be greatly appreciated!

 

[Sir Topham Hatt]

I'm no expert but we got an expert in to look at our place and we did increase our insulation, including extra insulation in the loft. So broadly I would suspect that going from 2 layers to 3 layers to be worth paying the couple of hundred to upgrade - as usual - "it depends" - but definitely worth looking at, IMHO.

 

[34C]

I have an old, cold house and the loft has a couple of rolls of what looks to be cheap insulation...

The current UK standard is 270mm of typical glass fibre roll insulation.

But some care is required relating to the construction of the 'old, cold house'. As suggested above, is advice available locally from someone who understands what can and cannot be done with whatever style of construction is present?

It is worth getting such advice in my opinion; there was a case locally of roof timber replacement because the late enthusiast for insulation had packed in enough to limit air circulation around some of the timber in what was built as a 'cold roof', and the result was the rafter ends on the wall plate developing serious wet rot. The roof construction was sufficiently robust that between massive purlins and bracing there was no risk of immediate failure, and it looked fine from outside, but the survey for the buyer picked up the damage for rectification.