Sealing a 1930's slate roof

[bexta]

Hello helpful people!

I live in an ex council, semi-detached, 1930's house which has a slate roof.
I have noticed lately that there is a fine grit, almost like sand covering everything in the loft. I'm pretty sure its coming off the back of the slate tiles which are cover in a paper like material (after googling for a while I think it is a paper felt insulation which was used back in the day.

My loft has already been highly insulated so I was thnking of removing all of this paper stuff as its already falling off and just painting the inside of the roof with a water sealant like this http://www.screwfix.c...Black%201kg&source=aw as an added layer of protection.

Can anyone tell me if this is safe, if I will cause any problems or suggest any other cheap alterantives?

[S_C]

your loft space area needs to be able to breath , otherwise you will find problems of damp from condensation or dry rot will occure . "
the " paper/ felt " is there to help insulate against wind and water coming in between the gaps of the slates.
the best option to repair the " break down " of this is to replace the felt , this would also give you a chance to check the " slats " thet your slates rest on .

however if this is to " expensive 2 an option for you at this time as long as you do not actualy have holes in this " paper " and are suffering other effects other than the " dusty " it can wait a while.

depending on your area " where you live " prices to remove the slates , replace the slats and the felt " recommend a breathable one" and replace the slats should be in the region of no more than approximately £1500 for a standard terranced house. as yours is an end house maybe another £500 should be allowed . remeber this is a rough estimate to the job not a quote or even a firm pricing as area can seem to make a big differance

[bexta]

Thanks for the reply, the professional option is way out of my price range at the moment!

The paper backing is almost non existant now anyway as most of its crumbled off, so there wouldn't be much to take off. I don't think there is enough left on the slates to be having any effect on water/wind proofing.

If the sealant option is not a good idea, what about expanding foam insulation? Thats supposed to prevent condensation and prevent the elements soming in through any gaps isn't it?

Thanks in advance

[S_C]

it is a viable option however cost wise to do the whole roof i wouldnt like to hazard a guess.
however when it is time to get work done on your roof you may find this option's problem.

if and when your slats need replacing and the slates will need to be removed for this . You may find that the insulation you have now put on will become a problem as the foam will get broken and need removing from the back of the tiles and the roof joists so creating further work and obviously added cost later.

however even with that said it maybe a viable option for the time being. all depends if you can save to have the job done correctly or this cheeper option. with the problem of paying extra later.
" this type of insulation i understand is usualy spayed under the felt " inside the loft " and therefore only normaly comes in contact wit hthe felt and the wooden beans in the loft not the slates or slats.

before posting this i checked on a site that specialise in this and they usualy fix the issues with the roof before doing this type of work . i would suggest they have good reason to do this for reasons i have already highlighted above
http://sprayfoaminsul...cqxp58CFVaY2Aod-BkN1A .

[AlBags]

You should leave these options well alone until you really need .. or have to replace roof covering. It's common for sand dust to fall from old felt or coatings. At the end of the day, the felt is only there as a draughtproofer. The slates are supposed to stop the water!
Then .. if you use/need loft space warm, use tyvek and celotex board.
If you don't need insulation, just have redone with felt.

[magicmerlin]

Whatever you do, I would suggest that you have it done professionally with a suitable warranty/guarantee etc.

Then if you decide to sell house it will show up in survey done by prospective buyers.

[johntaylor99]

Hi bexta
I had a similar problem when I moved into a 1915's house. I went to a builders merchant and bought a large roll of garden weed supressor and a hand operated staple gun. I stapled the material to the roof trusses like building a tent inside the roof. This material is breathable so no problem with condensation.After 6 years I still have a nice clean area where the loft is boarded. The whole process was very cheap. Hope this helps.
johntaylor99