Please forgive my question in English. I have spent now several hours trying to understand and find the answers to my questions in your forum but am still not confident enough to go shopping!
Of course I have a Fachwerk house and the problem is außen Dämmung (I've picked up a few words!)
The walls between the fach are a miy of Lehm and bricks. Inside we have used lehm as "plaster"
My Plan is two layers of 60mm mineralwool laid direct on the wall (eg Isover) the First vertical the second horizontal so there should be no gaps(of course held with a frameworks of 60mm latten)
This is to be covered with pvc sheets.
Bauplatten of some sort (recommedations welcome - cost is vry importent as we have had too many surprises and budget is tight)
If I can find some suitable wood (around 20mm thick and not all nice and straight) then I would like to create a "false" fachwerk and plaster between.
Have I got anything right?
Be grateful for any help/advice
Can you explain the purpose of doing that.
Saving heat energy, protect the timberframe, any architectural reasons?
Insulation from mineral Material is the not recommended to cover your timberframe in. Therefrom you have to bring in a windshild film with this kind of buildups.
If you have to and want to bring on an insulation from the outside you might get better with a wood fiberboard and a rear ventilated wooden boarding.
There is no need to pretend bricks and the timberframe, this will rot anyway (when using cheap timber) and increase your costs.
I'm not an expert but also have a "Fachwerkhaus" in Germany, am English and have read a lot in this forum.
In the past, a lot of mistakes were made renovating these old houses such as using materials like polystyrene, foam, breeze blocks, mineral insulation products, pvc etc. The problem with these materials is that moisture inevitably penetrates the walls at some time but cannot get out again, causing damp and rotting the beams. The houses look ok from the outside but are slowly rotting on the inside.
These days there is a movement towards using traditional materials (daub, lime plaster) and natural insulating materials like hemp, cotton, wool etc. The advantage of these materials is that they allow penetrating moisture to escape, keeping the beams dry.
As far as I have read in this forum, insulating half-timbered houses is a specialist field and it is easy to make mistakes. For example, you need someone to calculate the dew point etc. etc.
I hope this is of some help.
Thanks for the replies. The purpose of this is to save energy!
We have had an energy advisor tell us how much dämmung to use and where but I'm still trying to reach the decision as what material to use.
As I mentioned we have had several expensive surprises so money has become very tight!
Dear Mr. Skidmore, if you want to save energy, you can do it with Außendämmung. I hope your advisor has made a concept that fits to te "Energie Einspaar Verordnung" or made an "Abweichungsantrag" so that you cant get troble because the law. I think with 120 mm mineralwool you will fit in EnEV, may be it ist too much. Some hints to construct a "Vorhangfassade": If you put mineralwool two times around, you have to cover it with a very "dampfdiffusionsdurchlässiger" Folie (the Steam must get out). The Sd-Wert should be under 0,5 meters, better 0,2 meters, the dew point has to be calculated. Outside this you need some Latten that let the air get in at the bottom and get out at the top. Outside this you can take some "Bretter" to get the rainprotection by a type of "Schalung". Do not use a false Fachwerk, it will not hold the function and it will look very bad.
Yours Ulrich Arnold
Energy advisors will, of course, advise you to insulate your house as that is their job. Half-timbered houses were not intended to be insulated and insultating them in the wrong way can cause more damage and expense in the long run. There have been many discussions on this forum for and against insulation, and whether inside or outside insulation is better for Fachwerkhäuser.
As it takes years for the saving in heating costs to pay for the expense of the insulation measures and our budget was tight, too, we decided not to insulate our house but save heating costs by using a wood-burning stove. Our heating costs are low and the house always warm.
However, if you have decided insulation is the only way for you, I don't think you will find the answers on the Internet. You need an expert in insulation and Fachwerkhäuser to help you find the right solution - that could save you costs in the long run. There are also regulations that have to be met (EnEV) when you change the outside of your house, so you need an expert to make the necessary calculations and sign the required documents.
You can get very cheap loans from the KfW for insulating your house which you can apply for through a German bank. They have an English page: www.kfw-mittelstandsbank.de/EN_Home/Service/Loan_application.jsp.