Drywall/Plasterboard and Insulation Installation help needed!

the stuff on youtube may not be designed for exactly your conditions. Have a poke aroundhttp://www.energysavingtrust.org.uk/scotland and ask for help. You may be able to get someone to come look at it and give advice for free of tell you which type of professional to pay for. THEY then tell you how much an amateur can do and what a professional can do, they';re a charity so they won';t try to scam you into buying expensive services. you definitely need to ensure that you have adequate seals in place. My house is only 10 years old and they never sealed the kitchen before fitting it so there is a distinct draft in the winter. If wind can get in (in Scotland!!!) it will abolutley make a big difference to your heating bills.

What renovations have been done on your 160 year old cottage? Is it even drywall or is it http://en.wikipedia.org/wiki/Lath_and_plaster? Wikipedia suggests that's much less common in your part of the world, but still... Any risk of asbestos? Would you know it if you see it? What about other improvements you might have to make? I don't know what the building codes over there are like, but I think in the US if you tear off the wall and find something outdated (say, http://en.wikipedia.org/wiki/Knob_and_tube_wiring) you'd have to replace it.

I will say that in terms of the insulation you will want to use, it should probably be a closed foam spray insulation. You will need a professional to do this. It requires a lot of fancy and expensive spray equipment and you need to know what you are doing. It would basically involve stripping all of the exterior walls down to the studs and having a professional come in and spray and trim the dried foam to fit. You would probably want to do the whole cottage at once, but a room by room approach might be easier to do for your sanity. The liquid they spray on the walls expands to fill all of the crevices and provides an excellent vapor barrier. Since it fills all of the crevices, it also is excellent at sealing out cracks and the like. Check with the installer about getting the highest R-value possible. The higher the value, the better the insulation is, the less money it costs to heat and cool over time. Once you have the walls open and before you have they spray the insulation, you should replace all the wires, water pipes, place more studs in the wall, and anything else you need to do before filling the walls with insulation. This will be exponentially much harder once the insulation is there. I do not know what the standard is in the rest of the world, but in the US studs are generally 16 inches/40cm centered on the wall. When I have worked on older houses in the US, between 160 - 250 years old, this has not always been the case. Some studs have been slanted, horizontal, and generally in all sorts of weird angles. YMMV. Hanging drywall can be very easy to do. You basically start at the bottom of the wall and work your way up with the sheets. The sheets are hung with the wide side horizontal. Please use drywall screws, they are much less likely to pop out later. Cutting the drywall sheets is as easy as scoring them with a utility knife, then snapping them. If you can follow directions to cook fancy cakes and the like, then you can follow the directions to hang drywall. It is not hard, just labor intensive. The hard part about having drywall walls is taping the seams and patching the screw heads. This takes practice and patience to do well. Patching over the holes is just a matter of mounding the drywall compound over the holes, letting it dry, adding some more coats of drywall compound, letting those dry, then sanding smooth and painting/wallpapering. Seams require a coat of compound, tape being pressed into the wet compound, then more coats of compound over the tape until you have a mound, letting that dry, adding more compound as needed, then sanding smooth and painting. Please do not sand smooth until you expose the tape, you will need to add more compound then. If you want to search youtube for videos, they will give you an excellent overview of the process. Sites like http://www.thisoldhouse.com/toh/tv and http://www.diynetwork.com/ will have videos of the process. If either the drywall hanging or patching/taping ideas scare you, then you need to get a professional to do it, which will be a more expensive. The other option, is getting a handy friend, who knows what they are doing, to help you. Trust me, they are probably used to it and they may even like doing the work. Look at their house to see if they are any good. Either way, you will save money in the long run due to lower heating costs.

http://www.mgcltd.co.uk/sempatap-thermal is "recommended" by the Energy Saving Trust so I would trust that. I wouldn't just go putting it up willynilly though; I think you need a real plan. If places like EST won't come out to you, call your council. They may have a team who will come out to you (there are teams for the unlikeliest things lurking in councils...). If they cannot come out, order a http://www.amazon.com/exec/obidos/ASIN/B001LMTW2S/metafilter-20/ref=nosim/ and do your own inventory. If it turns out the walls are the real issue and you don't know what to do, pull off a panel of drywall and video what's back there. You need to know how your walls are constructed, if they are insulated, how, with what and to what thickeness. Then ask local people for local references and get some workmen in to give you quotes on what they think you need. Then go research all of the options. The post your video to MeFi if you're still not clear on what choice to make. A lot of this will be limited by what you can afford. Remember that if you ever want to sell this house, it's going to need an http://www.direct.gov.uk/en/homeandcommunity/buyingandsellingyourhome/energyperformancecertificates/dg_177026, and you can probably recoup some of the present cost in a later sale with a more efficient rating. If you want to wait until October, the http://www.decc.gov.uk/en/content/cms/tackling/green_deal/gd_customer/gd_customer.aspx kicks in and you may be able to fund the best insulating improvement available to you over time, though with the Green Deal you will not be able to DIY.

We live in a house built in 1890 about half mile from Lake Michigan in Chicago. The exterior walls are multi-layered. There is exterior masonry, more than a foot thick, then a dead space, then a brick wall, then the drywall. Ceilings are quite tall. Idiots replaced the boilers/radiators in the 1970's and you simply cannot heat the place above 66 degrees in the winter. So we had foam insulation blown into the drywall. The impact has been negligible in terms of our heating costs and ability to warm the place above the mid-60's. I would much rather we had spent the money and construction time on installing radiant heat flooring.

Probably echoing comments above, but absolutely get a professional. Find a company that can do a proper energy audit, describe the steps they intend to take and why, and give you a firm (or tight range) cost for the work. There are a lot of potential issues with these sorts of energy improvement projects. Energy flows from warmth to cold and moisture follows the energy. In many cases the durability of older structures is in part because of the constant flow of energy controlling moisture and the like. A poorly conceived project can trap moisture in bad locations where it might freeze or rot things, among other concerns. Careful and precise detailing of key conditions is also required. These are all factors that point against DIY work. Things you can DIY include demolition and potentially rehanging drywall, trim and paint. But, all of this is better done in the context of coordination with an energy contractor. Finally, the project cost should include a parallel energy audit (such as blower door test with infrared camera) at the end to verify the integrity of the work.

Disclosure - I work on the government project that I'm about to recommend (I helped do the website). You need to give the http://www.greenerscotland.org/warm-homes a ring. They will be able to help you work out what the best option is for insulating your home and let you know if you're eligible for any assistance. It's a service provided by the Energy Saving Trust for the Scottish Government.

If possible, get a professional who doesn't mind you watching over his shoulder and asking questions and generally learning how to go about it yourself in case smaller jobs crop up. You'll learn what you're in for, what kind of tools you'd need, etc, and can make a more informed decision next time. Consider taking the opportunity while the walls are down to install more power/light/network/aerial sockets, or wire upgrade if the wiring is ancient.

Have you checked more obvious sources of draughts - badly fitting doors and windows. Old fashioned sausage draught excluders on doors and heavy curtains, on doors and windows, can make a big difference. Do you have double glazing? And there's lots of useful information on the http://forums.moneysavingexpert.com/forumdisplay.php?f=77.