i have just purchased a house the ground vents are only one brick above ffl and the bricks around house are damaged and decaying in the house

You say your air bricks are 1 corse above ffl? Your air bricks should be below your ffl thats why its cold!!how old is your house if your house was built in the 1800's or early 1900's it will not have DPC some cases builders back then used slat as a DPC, is your damp rising more then 1m above ffl if it is then its not rising damp if it's high it could be just condensation problem. Has your house got a cavity if it has and has no insulation the government are now giving grants so you can have it installed, also is your attic insulated, also you could get your house air tested and see we're it's letting air out. As for damaged decayed bricks you can get them replaced' don't forget a brick is over 4inchs wide and usually it's only the first 5mm thats damaged that leaves a good 90mm of undamged brick so I would recommend calling out a bricklayer to remove a brick that's damaged and check if it's more then 15mm decay replace them.

Hi, so much to see, you will need a site visit, if you got timber floors sitting on sleeper walls then you should have air bricks to vent underneath i would have site visit from good builder you could put job on my builder read feedback then get a few ideas best wishes colin.

Are you sure these are your underfloor air flow vents or are they the old gas fire vents that used to be in to allow the gaseous air out and fresh air into a living room. Has your floor been changed over the past due to maybe damp problems from sleeper walls to concrete floor? maybe this could be part of your damp problem has the house been damp proofed in the past? signs of this would be drill hoes with a plug that looks like a wall plug around the outside of the house on the damp proof course as this can also cause damp through injection years later as of damp proofing the best option is to chop out 2 course and replace with 2 course of blues all around the exterior of the house